The Changing Demographic Picture of the UK

The Changing Demographic Picture of the UK National Statistician s Annual Article on the Population Karen Dunnell National Statistician The population of the UK is currently growing at its fastest rate since the 19s, increasing by two and a half per cent between mid-1 and mid- 6. While life expectancy continues to increase, fertility rates have also been increasing in the last five years and are currently at their highest level since 19. In addition, international migration has led to the UK population growing by an average of 5 people per day over the last five years. The population is also becoming increasingly diverse and mobile, and these factors make it increasingly challenging to measure population change accurately. This is the first of a series of annual reports on the population of the UK; these reports will provide an overview of the latest statistics on the population and will also focus on one specific topic - for this report the topic is fertility and, in particular, the impact of migration on fertility, but different topics will be covered in future years. The reports will also highlight the key strands of work being taken forward within the Centre for Demography in order to improve UK population statistics. More detailed information on the populations of Wales, Scotland and Northern Ireland are available in the annual demographic reports produced by the respective devolved administrations. 1 Overview of the Current Population of the UK In 6, the population of the UK stood at almost.6 million 2. This was a 7.5 per cent increase from 56.4 million in 1981, and a 2.5 per cent increase from 59.1 million over the last five years alone (Table 1). Between 1981 and 6, the populations of England, Wales and Northern Ireland increased by 8 per cent, 5 per cent and 13 per cent respectively, while the population of Scotland declined by 1 per cent. However, over the past five years, all four countries have experienced population growth. The UK population grew by almost one and a half million between mid-1 and mid-6, and at the fastest rate of growth since the 19s Within England between 1981 and 6, the populations of the East, East Midlands, South East, South West and London all increased by at least per cent. In contrast, the populations of the North East and North West declined by 3 per cent and 1 per cent respectively. However, over the last five years, all Government Office Regions within England have experienced population growth, the most rapid growth being in the East and East Midlands. Of the twenty-one local government areas with the largest population growth (8 per cent or more) between 1 and 6, twelve were in the East or East Midlands, four were in London and the South East, and three were in Northern Ireland. Of the fifty-one areas whose population declined between 1 and 6, fourteen were in Scotland, twelve were in the North of England, and eleven were in London and the South East (Figure 1). Although Northern Ireland has seen the largest population growth of the four UK countries over the past five years (3.1 per cent), 9

Table 1 Population estimates, mid-1981 to mid-6 UK, constituent countries and English Government Office Regions millions Percentage Increase mid-1981 mid-1986 mid-1991 mid-1996 mid-1 mid-6 1981-6 1-6 UK 56.4 56.7 57.4 58.2 59.1.6 7.5 2.5 England 46.8 47.2 47.9 48.5 49.4 5.8 8.4 2.7 North East 2.6 2.6 2.6 2.6 2.5 2.6-3.1.6 North West 6.9 6.8 6.8 6.8 6.8 6.9-1.3 1.2 Yorkshire & The Humber 4.9 4.9 4.9 5. 5. 5.1 4.6 3.3 East Midlands 3.9 3.9 4. 4.1 4.2 4.4 13.3 4.2 West Midlands 5.2 5.2 5.2 5.3 5.3 5.4 3.5 1.6 East 4.9 5. 5.1 5.2 5.4 5.6 15.5 3.8 London 6.8 6.8 6.8 7. 7.3 7.5.4 2.6 South East 7.2 7.5 7.6 7.8 8. 8.2 13.7 2.7 South West 4.4 4.5 4.7 4.8 4.9 5.1 16.9 3.7 Wales 2.8 2.8 2.9 2.9 2.9 3. 5.4 1.9 Scotland 5.2 5.1 5.1 5.1 5.1 5.1-1.2 1. Northern Ireland 1.5 1.6 1.6 1.7 1.7 1.7 12.9 3.1 Source: Mid-year population estimates, 1981 to 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency Belfast has seen a 3.5 per cent decline in its population over the same period, the largest of any local government area in the UK. Between 1 and 6, Northern Ireland saw the greatest population growth of the four UK countries, but the population of Belfast declined more than any other local government area within the UK. Population growth or decline is based on births, deaths and net migration. However, an area that is not experiencing large levels of population growth or decline may still be experiencing a large volume of migration moves when migration into and out of the area are considered together. Population turnover is measured as the number of moves into an area from elsewhere in the UK or overseas plus the number of moves out of an area to elsewhere in the UK or overseas per population. Of the 22 local government areas in England, Wales and Northern Ireland that had the highest annual volume of overall migration between mid-1 and mid-6 (18 moves or more per population), all were London boroughs except Cambridge, Oxford and Reading (Figure 2). Half of these areas of highest population turnover experienced either slower population growth than the UK average (2.7 per cent) or population decline (Table 2). This was due to moves into these areas being offset by moves out of the same area, hence resulting in little actual population change. For example, between 1 and 6, Lambeth had the tenth highest annual volume of migration in England and Wales but actually experienced slight population decline over this period. Mid-year population estimates only take into account international migration that is long-term, namely the migration of people who are coming to or leaving the UK for one year or more (see Box One). Box one Definitions of long-term and short-term migration Table 2 Local government areas in England, Wales and Northern Ireland with highest population turnover, comparison with population change, 1 6 Average Volume of Migration (moves per population) Population Change (per cent) Cambridge 28 7.3 City of London 28 5.4 Westminster 26 14.1 Oxford 26. Camden 24 12.3 Wandsworth 24 2.7 Hammersmith and Fulham 24 1.2 Isles of Scilly 24. Islington 23 3.4 Lambeth 22.5 Kensington and Chelsea 22 9.7 Haringey 21 2. Southwark 4.9 Reading 19 1.3 Tower Hamlets 19 5.8 Merton 19 3.5 Richmond upon Thames 19 3. Newham 19.4 Ealing 19.3 Brent 18.7 Hackney 18.6 Hounslow 18 1.2 Source: Mid-year population estimates, Office for, Northern Ireland Statistics and Research Agency The United Nations recommended definition of a long-term international migrant is a person who moves to a country other than that of his or her usual residence for a period of at least a year (12 months), so that the country of destination effectively becomes his or her new country of usual residence. From the perspective of the country of departure the person will be a long-term emigrant and from that of the country of arrival the person will be a long-term immigrant. This 12 month migrant definition is used for the UK usually resident mid-year population estimates and projections series. The United Nations recommended definition of a short-term international migrant is a person who moves to a country other than that of his or her usual residence for a period of at least 3 months but less than a year (12 months), except in cases where the movement to that country is for purposes of recreation, holiday, visits to friends and relatives, business, medical treatment or religious pilgrimage.

Figure 1 Population Change mid-1 to mid-6 United Kingdom Orkney Islands Shetland Islands Population change as a percentage 8 or over 4 to 7.9 to 3.9 under Average local authority population change = 2.7% London See Inset Isles of Scilly Source: Office for

Figure 2 Population Turnover mid-1 to mid-6 England, Wales and Northern Ireland Average annual volume of migration, moves per hundred population 18 or over 15 to 17.9 11 to 14.9 7 to.9 under 7 Average local authority migration per population =.8 See Inset London Source: Office for

Table 3 Population estimates, mid-6, and mid-6 based population projections 11 to 31 UK and constituent countries millions Percentage increase mid-6 mid-11 mid-16 mid-21 mid-26 mid-31 6 31 6 11 UK.6 62.8 65. 67.2 69.3 71.1 17.4 3.6 England 5.8 52.7 54.7 56.8 58.7.4 19. 3.8 Wales 3. 3. 3.1 3.2 3.3 3.3 11.1 2.4 Scotland 5.1 5.2 5.3 5.3 5.4 5.4 5. 1.7 Northern Ireland 1.7 1.8 1.9 1.9 2. 2. 14.8 4. Source: Mid-year population estimates, 1981 and 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency; 6-based National Population Projections, Office for Recently published experimental estimates of short-term migration 3 indicate that according to the UN recommended definition an additional 43, people were, on average, temporarily resident in England & Wales for work or study purposes at any given time during the year to mid-5. Of these, 16, were based in London. The UN definition only includes visits made for between three and 12 months. Experimental estimates show that over the year to mid-5, the flow of short-term migration was much higher (5, using the UN definition) than the population present at a given time which is inevitable given that such visits last for only a fraction of a year. The population of the UK is expected to continue to grow. It is projected that it will rise to 65 million by 16 (an increase of 7.2 per cent compared with 6), and will exceed 71 million by 31 4 (Table 3). The populations of all four constituent countries of the UK are projected to rise more quickly over the next five years than they have over the previous five years. Over the next 25 years, the populations of England, Wales, Scotland and Northern Ireland are projected to increase by 19 per cent, 11 per cent, 5 per cent and 15 per cent respectively. It is projected that the population of the UK will increase by over million (17 per cent) by 31. Age Structure of the UK Population The population of the UK is ageing. In 1981, 22 per cent of the population was aged under 16 while 15 per cent of the population was aged 65 and over (Figure 3). Compared with 1981, there were over a million fewer children in the UK population in 6 (19 per cent of the population) and over 1.2 million more people aged 65 and over (16 per cent of the population). The UK population of persons aged 16 64 increased by 4. million between 1981 and 6. The average (mean) age of people in this group increased from 38 years to years over the same period. Figure 3 Estimated age structure of the UK population: mid-1981 and mid-6 Figure 4 Estimated and projected age structure of the UK population: mid-6 and mid-31 Males (thousands) Source: Mid-year population estimates, 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency; 6-based National Population Projections, Office for Millions Figure 5 Estimated and projected UK population aged 65 and over 8 6 4 2 31 31 65 74 75 84 85+ 6 9 7 5 3 6 Females (thousands) 7 mid-1981 mid-6 mid-31 6 5 3 6 1981 1981 Males (thousands) Females (thousands) Source: Mid-year population estimates, 1981 and 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency Source: Mid-year population estimates, 1981 and 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency; 6-based National Population Projections, Office for It is projected that the population of the UK aged 65 and over will rise by 63 per cent to 15.8 million over the next 25 years, while the population aged under 16 will rise by just 11 per cent to 12.8 million (Figure 4). It is projected that in 7, for the first time, the population of state pensionable age (65 and over for men and and over for women) will exceed the number of children under 16. By 31 it is projected that persons aged under 16 will make up 18 per cent of the UK population, while those aged 65 and over will account for 22 per cent of the UK population. Over the same period, the population aged 16 64 is projected 13

to rise by 8 per cent (3.2 million) to 42.5 million, with the average (mean) age of persons in this age group rising slightly from. to.3 years. Table 5 UK population by ethnic group, 1 In 1981, just 1 per cent of the population were aged 85 and over. Over the last 25 years, the number in this age group has more than doubled to 1.2 million (Figure 5), with those aged 85 and over now representing 2 per cent of the population. Indeed, the estimated number of people aged 85 and over rose by 6 per cent in just one year between mid-5 and mid-6, and over the next 25 years it is projected that the number of people in this age group will more than double to 2.9 million, meaning that 4 per cent of the UK population will be aged 85 or more. The estimated number of people aged and over in the UK reached almost, in 6, and by 31 it is projected that this number will increase six-fold to 59,. By 31, it is projected that 2.9 million people will be aged 85 or more (4 per cent of the total UK population), of whom 59, will be aged or more. The ageing of the population, and in particular the projected doubling of the population aged 85 or more over the next 25 years, will have major implications for future policy and service provision. Analyses based upon the results of the General Household Survey for Great Britain 5 have indicated that when interviewed, over per cent of those aged 85 and over had visited their GP within the last two weeks and over 25 per cent had visited hospital as an out-patient in the last 3 months. In 1, over per cent of men and over per cent of women aged 85 and over lived in communal establishments. For the remainder living in private households, over per cent of men and 7 per cent of women aged 85 and over lived alone. Dependency ratios are measured as the number of children (those aged 15) and persons of state pensionable age (currently and over for women and 65 and over for men) per people of working age (16 59 for women and 16 64 for men). The overall dependency ratio has fallen from 67 to 61 in the last 25 years (Table 4), due to the rise in the working age population combined with the fall in the number of children outweighing the rise in the number of persons of state pensionable age. It is projected that the dependency ratio will increase a little to 64 by 31 despite the forthcoming changes in the state pension ages for both men and women 6. Characteristics of the UK Population Ethnicity In 1, 8 per cent of the UK population belonged to a non-white ethnic group 7. This percentage varied for the four UK countries (Table 5) while 9 per cent of the population of England were non-white, the percentages for Wales, Scotland and Northern Ireland were much lower (2 per cent, 2 per cent and.7 per cent respectively). The latest experimental population estimates by ethnic group for England 8 indicate that between mid-1 and mid-5 the population belonging to non-white ethnic groups increased by 945,, accounting for almost 11 per cent of the English population in mid-5. Table 4 Estimated and projected UK dependency ratios, 1981, 6 and 31 Number per persons of working age: Children Persons of State Pensionable Age All Dependents mid-1981 37 3 67 mid-6 31 3 61 mid-31 29 34 64 Source: Mid-year population estimates, 1981 and 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency; 6-based National Population Projections, Office for. England Wales Scotland Northern Ireland Percentages United Kingdom White Groups 9.9 97.9 98. 99.3 92.1 Non-White Groups: 9.1 2.1 2..7 7.9 Mixed 1.3.6.3.2 1.2 Asian or Asian British 4.6.9 1.1.2 4. Black or Black British 2.3.2.2.1 2. Chinese or other ethnic groups.9.4.5.3.8 All ethnic groups..... Source: Census 1, Office for, General Register Office for Scotland, Northern Ireland Statistics & Research Agency The age structure of the different ethnic groups within the UK population differs greatly (Figure 6 note that the population in white ethnic groups is far larger than that in any of the other groups and thus the scales differ between the charts). While the average (mean) age of those in White ethnic groups was years in 1, the corresponding average ages of those in Black, Asian and Mixed ethnic groups were 31, 29 and 21 years respectively. The very young age structure of the Mixed ethnic groups reflects the increasing prevalence of inter-ethnic partnerships. In 1, two and a half per cent of couples (married and cohabiting) in England were from different ethnic groups. Whilst the average age of those in White ethnic groups was years in 1, the corresponding average ages of those in Black, Asian and Mixed ethnic groups were 31, 29 and 21 years respectively Country of birth In 1981, just over six per cent of the UK population had been born overseas. By 1, this had risen to over eight per cent, and latest estimates from the Labour Force Survey indicate that in 6 almost ten per cent of the UK population were born overseas. Between 1 and 6, the estimated number of people living in the UK who were born in the eight Central and Eastern European countries that joined the European Union in May 4 (known as the A8 countries) rose to over,. Despite this recent rise, this group still only accounts for seven per cent of the total overseas-born population of the UK (Figure 7). In 6, almost per cent of the UK population were born overseas Households and Families In 6, there were just under 25 million households 9 in the UK, a rise of over per cent since 1981 (Figure 8). While the number of multiple person households rose by just 9 per cent over this period, the number of single person households rose by 65 per cent. Much of this rise in single person households was as a result of people of working age being increasingly likely to live alone. In 1981, approximately two-thirds of single person households were people of the state pensionable age, but this had fallen to approximately half by 6. It is projected that the number of households in the UK will rise to 3 million by 21, of which over a third will be single person households. There were an estimated 17 million families 9 living in the UK in 6. Over the last years, the number of married couple families has fallen slightly, while the number of cohabiting couple families has increased by over per cent (Figure 9). While there were over 1, more lone parent families in 6 than in 1996, the estimated number of single father families actually fell slightly over this period. 14

Figure 6 Age structure of the population of Great Britain by ethnic group White Ethnic Groups 7 5 3 Mixed Ethnic Groups 7 5 3 5 3 3 5 Males (thousands) Females (thousands) Asian Ethnic Groups 7 5 3 3 3 Males (thousands) Females (thousands) Black Ethnic Groups 7 5 3 3 3 Males (thousands) Females (thousands) Source: Census 1, Office for, General Register Office for Scotland 3 3 Males (thousands) Females (thousands) Figure 7 Overseas-born population of the UK by selected country of birth, 6 Figure 8 Households by type, UK, 1981-6 3. 2.5 2. 3 25 Single person households Multiple person households Millions 1.5 1..5 A8. Irish Republic Rest of EU Old India/ Commonwealth Pakistan/ Bangladesh Source: Labour Force Survey, Office for Components of Population Change Rest of the World Increases in the number of births, decreases in the number of deaths, and changes in the pattern of international migration into and out of the UK have all contributed to population growth over the last twenty-five years (Figure ). While natural change, the difference between the numbers of births and deaths, has remained relatively constant, adding an average of, people to the UK population each year, the contribution of international migration to population change has been far more variable. Between mid- 1981 and mid-1986, the effect of net migration was to reduce the population slightly. This is in sharp contrast to recent years when net migration has Millions 15 5 1981 1991 1 6 Source: Censuses, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency; Household Estimates, Communities and Local Government, Scottish Executive; Labour Force Survey, Office for been the predominant driver of population change. Between mid-1 and mid-6, net migration and other changes accounted for almost two-thirds of the 1.5 million growth in the UK population (not including the impact that net migration had upon the number births in the UK). Births In 6 there were 749, live births in the UK, up almost 12 per cent from 669, in 1. The total fertility rate (TFR, see Box Two) in the UK has consistently risen since 1 from a record low of 1.63 children per woman to 1.84 children per woman in 6. This is the highest 15

Figure 9 Families by type, UK, 1996 and 6 15. 1996 6. Millions 5. The total fertility rate in the UK has consistently risen since 1 from a record low of 1.63 children per woman to 1.84 children per woman in 6 Over the last twenty-five years, the TFR for Northern Ireland has remained higher than that for the UK as a whole, but the difference between the two has narrowed from over.7 children per woman in 1981 to just.1 children per woman in 6. Since the mid-19s the TFR for Scotland has been.1 to.2 children per woman lower than that for the UK as a whole. The recent rises in fertility rates have resulted in the TFR for England and Wales in 6 being similar to that observed in 19. The TFR for Wales was higher than that for England during the 199s, but has been very similar to that for England since 1.. Source: Labour Force Survey, Office for Figure Lone father family Lone mother family Married couple family Cohabiting couple family Components of population change, UK, mid-1981 to mid-6 Box two Glossary of Demographic Terms Age-Specific Fertility Rate (ASFR) The number of live births in a year to women aged x, per thousand women aged x in the mid-year population. Millions 2. 1.5 1..5 Natural change Net migration and other changes Total Fertility Rate (TFR) The average number of children a group of women would have if they experienced the age-specific fertility rates for a particular year throughout their child-bearing life. For example a TFR of 1.84 in 6 means that a group of women would have an average of 1.84 children each during their lifetime based solely on 6 s age-specific fertility rates. This measure reflects the current intensity of childbearing and the rate at which the population is replacing itself, rather than completed family size...5 Source: Mid-year population estimates, 1981 to 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency. Children per woman Figure 11 4. 3.5 3. 2.5 2. 1.5 1981 1986 1986 1991 1991 1996 1996 1 1 6 Total fertility rate, UK and constituent countries, 1961 to 6 1. 1961 1966 1971 1976 1981 1986 1991 1996 1 6 Source: Birth registrations data and mid-year population estimates, 1961 to 6: Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency. TFR since 19, but is still below replacement level (see Box Two) and much lower than the rates seen during the 19s baby boom (Figure 11). The recent rise in the TFR has occurred in all four countries of the UK. Several other countries around the world have also experienced increasing TFRs over the past five years including France, Sweden, Denmark, Finland and Australia. UK England & Wales Scotland Northern Ireland Replacement Fertility Level The level of fertility required to ensure a population replaces itself in size. In the UK, as in all developed countries, a fertility rate of 2.1 is usually taken as roughly approximate to the level of replacement fertility. Completed Family Size (CFS) The average number of children that women born in a particular year have had by the end of their childbearing years. This measure takes into account changes in the timing of childbearing between generations, but is not a timely measure of family size as it is based upon women who have completed their childbearing. Age-standardised Mortality Rate Age-standardised mortality rates cover all ages and are standardised to the European Standard Population, expressed per million population; they allow comparisons between populations with different age structures, including between males and females over time. Period and Cohort Life Expectancy Period life expectancy is calculated using the age-specific mortality rates for a given period (either a single year or a run of years) with no allowance for any later actual or projected changes in mortality. It provides a useful statistic for summarising mortality rates over a given period, but it does not reflect the length of time a person would expect to live since it does not allow for known or assumed changes in future mortality rates as that person ages. Cohort life expectancy is calculated using known or projected mortality rates as a person ages. It therefore reflects the length of time a person would expect to live. 16

The continued rise in UK fertility rates over recent years has led to the first rise in the long-term fertility assumption used for producing the National Population Projections since the 19s baby boom. For the latest 6-based projections, a completed family size of 1.84 children per woman has been assumed for the long-term compared with the previous assumption of 1.74 children per woman used for the 4-based projections. Deaths In 6 there were 572, deaths registered in the UK 11, 274, for men and 298, for women. Age-standardised mortality rates (see Box Two) in England & Wales for males and females were 7,123 and 4,989 deaths per million population respectively. These rates have fallen steadily since 1981, with the male rate falling by 42 per cent and the female rate falling by 33 per cent (Figure 12). Over the last 5 years alone, there has been a 13 per cent fall in the male age-standardised death rate and a per cent fall in the female rate, with the difference between the male and female rates in 6 being the lowest ever recorded. Period life expectancy (see Box Two) in the UK has risen steadily over the past 25 years (Figure 13). Latest estimates 12 indicate that based on mortality rates in 4-6, compared to mortality rates experienced in 19-1982, life expectancy for newborn boys has risen by six years to 76.9 years, while that for newborn girls has risen by over four years to 81.3 years. These estimates of life expectancy do not take into account projected improvements in mortality during the lifetime of children born in 4 6. Allowing for the projected mortality improvements assumed in the 6-based population projections, cohort life expectancy at birth in 5 is 88. years for boys and 91.3 years for girls. Greater than expected falls in mortality over the last two years have led to increases in the assumptions related to life expectancy used for producing the National Population Projections. For the latest 6-based projections, the UK assumption for period life expectancy at birth in 31 is 82.7 years for men and 86.2 years for women, a rise of 1.3 years and 1.2 years respectively when compared with the assumptions for 31 used for the 4-based population projections. While the assumptions for 31 include improvements in mortality rates between now and 31, they do not take into account improvements beyond 31. Cohort life expectancies at birth (that include allowance for further improvements in mortality rates beyond 31) are 8.6 years higher for men and 8. years higher for women compared to the equivalent period measures. Migration In 6, 191, more people came to live in the UK for a year or more than left to live overseas 13 (Figure 14). An estimated 591, long-term Figure 13 Period life expectancy at birth, 19 82, 4 6 and 31 Expectation of life at birth (years) Men Women Source: Interim Life Tables and National Population Projections, Office for Figure 14 Thousands 9 85 75 7 65 5 3 Total international long-term migration to and from the UK, 1991 to 6 Source: Total International Migration estimates, Office for Figure 15 1991 19 82 4 6 31 Immigration Emigration 1992 1993 1994 1995 Net migration 1996 1997 1998 1999 Net international long-term migration to the UK by citizenship, 4 to 6 1 2 3 4 5 6 Figure 12 Age-standardised mortality rate by sex, England & Wales, 1981 to 6 Thousands A8 Rate per million population 14, 12,, 8, 6, 4, 2, Males Females British European Commonwealth Other Union foreign Source: Total International Migration estimates, Office for international migrants (see Box One) arrived to live in the UK, of whom 5, (86 per cent) were non-british citizens. The estimated number of people emigrating from the UK reached a record high of, in 6, of whom just over half (7,) were British citizens. 1981 1986 1991 1996 1 6 Source: Death registrations data and mid-year population estimates, 1981 to 6: Office for In 6, 191, more people came to live in the UK for a year or more than left to live overseas 17

In the three year period from 4 to 6, citizens of the eight Central and Eastern European countries that joined the EU in May 4 (known as the A8 countries) accounted for 13 per cent of total long-term immigration and 4 per cent of total long-term emigration. There was thus a net migration of 1, A8 citizens to the UK over this period, compared with long-term net inflows of, citizens of other EU countries, 4, Commonwealth citizens, and 2, other foreign citizens. Over the same period, there was a long-term net emigration of 3, British citizens (Figure 15). The continued high level of international migration to the UK over recent years has contributed to a rise in the long-term assumption for net migration used for producing the National Population Projections. For the latest 6-based projections, a net international migration inflow of 19, each year has been assumed, compared with the previous assumption of 145, a year used for the 4-based projections. However,, of this increase is attributable to a methodological change following the announcement earlier this year of improvements to the estimation of international migration 14. Focus on Fertility As already outlined, the total fertility rate (TFR, see Box Two) in the UK has been rising over the past five years from a record low of 1.63 children per woman in 1 to 1.84 children per woman in 6, the highest level since 19 (Figure 11). Trends in age-specific fertility rates have also been changing in recent years (Figure 16). The general trend over the last twenty-five years in the UK and all the constituent countries has been of falling fertility at younger ages alongside rising fertility at older ages. This has led to a steady increase in the mean age of childbearing in the UK. In 1981 the mean age of women at childbirth was 27 years but by 6 this had risen to 29 years. Since 2, fertility rates have continued to rise at older ages, but there have also been small rises in fertility rates for women in their twenties. This rise in the fertility of younger women has been particularly unexpected and it is not clear whether this trend will continue over future years. Fertility can also be analysed from a cohort perspective by considering family size achieved at selected ages by women born in different years. There has been a steady decline in achieved family size for cohorts born since the mid-19s (Table 6). Among women who have already reached age 45, average family size fell from 2.22 children for the cohort born in 1945 to 1.98 for the cohort born in 19. Similarly, women born in 1965, 197 and 1975 have had steadily fewer children by ages 25 and 3 Table 6 Year of birth than earlier cohorts. However, although achieved fertility by age 3 has been falling, the 1965 and 197 cohorts have partly caught up because of higher fertility in their thirties. For example, women born in 197 had.44 children on average between ages 3 and 35 compared with.38 children for women born ten years earlier. In a marked change in the trend seen previously where each successive cohort has achieved slightly lower fertility at each age, women born in 19 had achieved the same family size by age 25 as the 1975 cohort. It remains to be seen whether the upturn in fertility for women aged to 29 since 2 will lead to higher completed family sizes for women born during the 19s or whether these most recent cohorts will have relatively lower fertility in their thirties to compensate. Factors influencing fertility Achieved family size by age of woman 25 3 35 45 1945.35 1.24 1.87 2.12 2.21 2.22 195.36 1.7 1.67 1.97 2.7 2.9 1955.31.93 1.54 1.88 2.1 2.3 19.24.81 1.42 1.81 1.96 1.98 1965..71 1.29 1.7 1.87 197.22.67 1.19 1.63 1975.21.59 1.9 19.22.59 1985.19 Average achieved family size by age, UK, selected birth cohorts Source: Birth registrations data and mid-year population estimates, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency In most developed countries, fertility rates for women in their thirties and forties have been increasing since the mid-197s. Women have been increasingly delaying their childbearing for a variety of reasons including wider participation in higher education, increased proportions of women in full-time employment, later marriage and partnership formation, and medical advances that have enabled childbearing at older ages. Previous studies 15 have shown that women with higher education qualifications tend to have children later in life and are more likely to be childless. Over the last years, there has been a large increase in the proportion of women in the UK who have a higher education qualification. Labour force participation by women can also lead to Figure 16 Age-Specific Fertility Rates, UK, 1981-6 Figure 17 Percentage of women in full-time or part-time work, UK, 1986-6 Live births per 1, women 1 1 3-34 25-29 -24 35-39 Under and over 1981 1986 1991 1996 1 6 Source: Birth registrations data and mid-year population estimates, 1981 to 6, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency Percentage 1986 1991 1996 1 6 18 24 25 34 35 49 Age Source: Labour Force Survey, Office for 18

Figure 17 18 Live births by country of birth of mother, UK, 6 Table 7 Estimated total fertility rates by country of birth of mother, England & Wales, 2 and 6 Mother born in: UK Republic of Ireland Estimated Total Fertility Rate 2 6 UK born 1.5 1.7 Born outside UK 2.3 2.5 Source: Birth registration data and populations by country of birth from the Labour Force Survey, Office for Other EU25 country India/Pakistan/Bangladesh Other countries Figure 19 1 Change in estimated age specific fertility rates for UK born and non-uk born women, England and Wales, 2 6 Source: Birth registration data, Office for, General Register Office for Scotland, Northern Ireland Statistics and Research Agency postponement of fertility. The percentage of women aged 25-49 working full-time or part-time has increased over the last years (Figure 17), although there is some indication that this rate of change has slowed over the last five years. In contrast to women in their thirties and forties, fertility rates for women in their twenties decreased steadily in the UK throughout the 19s and 199s. However, since 1, fertility rates at these ages have stopped falling and in the 25 29 age group have started to increase. Possible explanations for this change may be changes in maternity leave, taxation and benefits for those with children, and also the impact of recent high levels of international migration to the UK. Impact of international migration on births In the decade 1996 to 5, an estimated 1.8 million women of childbearing age arrived to live in the UK and 1.1 million UK resident women of childbearing age left the UK. In 1, 15 per cent of births in the UK were to mothers born outside the UK and by 6 this had increased to almost 21 per cent of births in the UK. The largest groups of mothers born outside the UK are those born in Pakistan, India and Bangladesh, who together accounted for 5 per cent of all births in the UK in 6 (Figure 18). The number of births to mothers born in EU countries other than the UK and the Republic of Ireland increased by 87 per cent between 1 and 6 and accounted for almost 4 per cent of all births in the UK in 6; this reflects the large impact that expansion of the EU in 4 has had upon international migration to the UK. Although international migration is certainly having an impact on UK births, the relationship between international migration and fertility is not at all straight-forward. International migration can affect the number of births in two different ways. First, it can affect both the size and age structure of the female population of childbearing age and thus the number of women who can potentially have children. Analysis of births in England & Wales in 6 indicates that net international migration between mid-5 and mid-6 increased the number of births in 6 by 7, solely due to the impact of both immigration and emigration upon the size and age structure of the UK population (this estimated impact is based on the assumption that immigrants, emigrants and the UK population have the same fertility rates). The second way in which migration can impact on fertility is if there are differences between the eventual completed family size of in-migrants and out-migrants compared to the non-migrant population. Migration may also have an effect on the timing of childbearing, for example if births are accelerated or postponed around the time of migration, and can hence affect the period TFR measure. Age-specific fertility rate 1 1 6 6 2 2 non-uk born UK born 15 19 24 25 29 3 34 35 39 + Age Source: Birth registration data and populations by country of birth from the Labour Force Survey, Office for In 6 the estimated TFR in England and Wales for women born outside the UK was 2.5, notably higher than the estimated TFR of 1.7 for UK born women (Table 7). However non-uk born women are not a homogenous group. Some groups have much higher fertility on average than UK born women, in particular those born in Pakistan and Bangladesh. Other groups have fertility rates far more similar to those born in the UK, including women born in other EU countries, Old Commonwealth countries, China and Hong Kong. Between 2 and 6 in England & Wales, the estimated TFR for women born in the UK increased from 1.5 to 1.7, while the estimated TFR for women born outside the UK rose from 2.3 to 2.5. When these rates are decomposed by age group (Figure 19), the fertility of women born outside the UK has increased more in the 25 29 and 3 34 age groups than it has for women born in the UK, and it therefore appears that international migration, to some extent, has been contributing to the recent increase in fertility rates in the 25 29 and 3 34 age groups. In contrast, the small increase in the fertility of women aged 24 appears to have been driven by UK born women. Similarly, information on women s intentions with respect to family size from the General Household Surveys of to 5 for Great Britain show that women born outside the UK have slightly higher intended family sizes at each age than UK born women. Women born outside the UK are more likely than UK born women to be intending to have large families, for example 18 per cent of women born overseas aged 3 34 stated that they intended to have four or more children, compared to just 11 per cent of UK born women of the same age. Analysis of actual family size indicates that women born overseas are indeed more likely to have larger families than UK born women, but are also more likely than UK born women to remain childless. International migration has clearly had an impact on the number of births in the UK over recent years. Although it does not on its own explain the 19

rise in the TFR for the UK over the past five years, analysis suggests that it has indeed contributed to this rise. The higher average fertility of women born overseas, especially those born in countries such as Pakistan and Bangladesh, is of particular relevance when considered alongside the relatively young adult age structure of the UK population of Asian ethnic origin (Figure 6). However, preliminary analysis comparing fertility rates for, say, women born in Pakistan with women of Pakistani ethnic origin (which will include second and subsequent generation migrants) suggests that the fertility of second and subsequent generation migrants is lower than that of first generation migrants, and may be converging towards the fertility levels observed for UK born women. This focus section has outlined some of the latest research relating to fertility in the UK, but more detailed articles on some of the issues discussed here are planned for future editions of Population Trends, including an article in the next edition describing in detail the background to the fertility assumptions used in the latest 6-based population projections for the UK. Looking to the Future As this article has described, the UK population is currently experiencing a period of rapid growth, while at the same time becoming increasingly diverse and mobile. These factors make it increasingly challenging to measure population change accurately. To respond to this challenge and the need to improve the quality and coherence of population statistics across the UK, the Centre for Demography (NSCD) was formed at the end of January 6. The NSCD work programme 16 is overseen by the UK Population Committee, and advice and guidance are provided by an Advisory Board of demographic experts. A key aim of the NSCD work programme is to minimise and better understand the future divergence between the rolled forward and Census-based population estimates. When population estimates first became available based on the 1 Census they were substantially lower than those rolled forward from the previous 1991 Census, and several revisions were subsequently made to the population estimates for England & Wales following extensive work by ONS to reconcile these differences. A key objective for our future development work within NSCD is to ensure that in producing inter-censal population estimates and projections, methods and data sources are of the highest possible quality, definitions are relevant to current patterns of population change, and full use is made of available and future data sources. It is clear that many of our stakeholders and users of population statistics, including across central and local government, want to see further improvements in population and, more specifically, migration data. This is understandable at a time of significant population change which is impacting on our economy, society and services. Some improvements have been introduced by ONS this year to the methods used for producing population statistics for England & Wales 14. Improvements to the methods for estimating international migration, and more specifically the methods by which these estimates are distributed between local authority areas within England & Wales, were introduced in August 7 when 6 midyear population estimates for England & Wales were first released. ONS has also begun to address the need for information on the numbers and characteristics of people entering and leaving the UK for periods of less than 12 months. As discussed in this article, such people are not included in population estimates and projections, but they can, nonetheless, have a major impact on the economy and service provision, particularly at a local level. ONS has recently released experimental estimates of short-term migration stocks and flows for England & Wales using a range of different definitions 3 and further work is planned on the feasibility of distributing these national estimates down to local authority level. However, these changes are only steps in the right direction and we recognise that more needs to be done. Over the past decade, migration has become the main driver of population change within the UK (Figure ), and it will continue to be a major focus of future development work. The report of the inter-departmental Task Force into improving international migration statistics published last year 17 explained the difficulties associated with accurate measurement and estimation of migration and stressed the importance of sharing information and collaborative working across government in order to secure improved migration statistics. The Task Force made a number of recommendations: some of the most important of these relate to more comprehensive counting of people at places of entry and exit to the United Kingdom, and the potential use of administrative data sources to identify better the numbers and locations of people in the country at any point in time. In planning for 8/9 and beyond, ONS will publish details of how the recommendations can be taken forward, while recognising that it will require a significant cross-departmental effort to deliver them. Work on some of the recommendations is already underway, such as improving the coherence of reporting on migration across Government. One specific recommendation of the Task Force was to improve the targeting of migrants within a port survey, and ONS has recently reported on an ongoing review of port surveys 18. As a result of findings of the review to date, additional filter shifts will be introduced to the International Passenger Survey in April 8 to boost the sample size of migrants travelling through Manchester, Stansted and Luton airports. These changes are further steps in the right direction and will build upon the extension of such filter shifts to better capture out-migrants as well as in-migrants from January 7. The review team are now conducting further work in order to recommend more significant changes from 9. Similarly, preliminary work has started on seeing how our household surveys could be strengthened, including some initial scoping and feasibility work on extending the surveys to cover communal establishments. While migration is a key focus of development work within NSCD, it is not the only area of research. For example, with the aim of giving users better information on uncertainty and the expected accuracy of population projections, ONS is currently investigating the use of stochastic forecasting techniques to produce probabilistic projections of the UK population. In addition, the Welsh Assembly Government is currently investigating the possibility of using a different methodology to produce population projections at local authority level. This new methodology is based on a bottom-up approach taking into account information at a local level and it is hoped that new population projections for areas in Wales will be published in early 8. While most of the development work within NSCD is focussed upon improving inter-censal estimates and projections of the population, active input is also being provided into the development of the 11 Census 19 and the Integrated Household Survey. Work is ongoing to ensure that all population groups are well-defined and enumerated in the Census; potential new questions are under consideration and data collection methods are being designed with the overall aim of maximising response. Together with the implementation of further improvements to inter-censal population estimates and projections over the coming years, this work should indeed help to minimise the discrepancy between rolled-forward and Census-based population estimates in 11, and to improve the understanding of whatever level of discrepancy does eventually occur. Finally, but also significantly, the NSCD work programme recognises that the impacts of the current population change need to be worked through and reported on. ONS and the devolved administrations have been looking increasingly to free up resources from the production of statistics to carry

out more demographic analysis and reporting. Some of this work does not necessarily have to be done by the National Statistical Office itself but could be done in partnership with other organisations and we are looking at possibilities in this area, including with the Economic and Social Research Council (ESRC). The improvements planned for our population and migration statistics, coupled with an enhanced level of demographic analysis and reporting, should improve the quality of what we can offer customers, for example to support the planning of services, as well as enhance the input NSCD can make to the policy debate in this area over the coming years. Notes and References 1 a) Welsh Assembly Government (7) Wales s Population: A Demographic Overview 1971-5. Available at: http://www.wales. gov.uk/statistics b) General Register Office for Scotland (7) Scotland s Population 6: The Registrar General s Annual Review of Demographic Trends. Available at: http://www.gro-scotland.gov.uk/statistics/ publications-and-data/annual-report-publications/rgs-annualreview-6/index.html c) Northern Ireland Statistics & Research Agency (7) Registrar General Northern Ireland Report 6. Available at: http://www.nisra.gov.uk/demography/default. asp?cmsid=_45&cms=demography_publications&release= 2 Office for (7) Information on latest UK Population Estimates available at: http://www.statistics.gov.uk/cci/ nugget.asp?id=6 3 Office for (7) Research Report on Short-term Migration. Available at: http://www.statistics.gov.uk/about/data/ methodology/specific/population/future/imps/updates/downloads/ STM_Research_Report.pdf 4 Office for (7) Information on latest UK Population Projections available at: http://www.statistics.gov.uk/cci/ nugget.asp?id=1352 5 Tomassini (5): The demographic characteristics of the oldest old in the United Kingdom, Population Trends 1 and Tomassini (6): The oldest old in Great Britain: change over the last years, Population Trends 123. Both available at: http://www. statistics.gov.uk/statbase/product.asp?vlnk=633 6 Under the provisions of the Pensions Acts of 1995 and 7, state pension age will (i) change from 65 years for men and years for women to 65 years for both sexes by and then (ii) increase in three stages to 68 years for both sexes between 24 and 46. Further details are available at: http://www.gad.gov.uk/demography_ data/population/6/methodology/pensionage.asp 7 Office for (6) Focus on Ethnicity & Identity. Available at: http://www.statistics.gov.uk/focuson/ethnicity/ 8 Office for (7). Information on latest experimental population estimates by ethnic groups available at: http://www.statistics.gov.uk/statbase/product.asp?vlnk=14238 9 A household is defined as a person living alone or a group of people who have the same address as their only or main residence and with common housekeeping (for example, the 1 Census defined this as those who either share one meal a day or share the living accommodation). A family is defined as a married or cohabiting couple, with or without their never-married child(ren) of any age, including lone parents with their never-married child(ren). A family could also consist of a grandparent or grandparents with grandchild(ren) if the parents of the grandchild(ren) are not usually resident in the household. For further information and analysis, see Office for National Statistics (7) Focus on Families. Available at: http://www. statistics.gov.uk/focuson/families/ a) Office for (7) Latest information on births in England & Wales available at: http://www.statistics.gov.uk/cci/ nugget.asp?id=951 b) General Register Office for Scotland (7) Latest information on births in Scotland available at: http://www.gro-scotland.gov.uk/ statistics/births.html c) Northern Ireland Statistics & Research Agency (7) Latest information on births in Northern Ireland available at: http://www. nisra.gov.uk/demography/default.asp?cmsid=_45_71&cms=demog raphy_publications_births+and+deaths+press+release&release= 11 a) Office for (7) Latest information on deaths in England & Wales available at: http://www.statistics.gov.uk/cci/ nugget.asp?id=952 b) General Register Office for Scotland (7) Latest information on deaths in Scotland available at: http://www.gro-scotland.gov.uk/ statistics/deaths.html c) Northern Ireland Statistics & Research Agency (7) Latest information on deaths in Northern Ireland available at: http://www. nisra.gov.uk/demography/default.asp?cmsid=_45_71&cms=demog raphy_publications_births+and+deaths+press+release&release= 12 Office for (7) Latest information on life expectancy available at: http://www.statistics.gov.uk/cci/nugget. asp?id=168 13 Office for (7) Information on latest UK Total International Migration estimates available at: http://www.statistics. gov.uk/cci/nugget.asp?id=2 14 Office for (7) Information on improved methods for population statistics revisions in 7 available at: http:// www.statistics.gov.uk/statbase/product.asp?vlnk=14834 15 For example, Rendall and Smallwood (3): Higher qualifications, first-birth timing and further childbearing in England and Wales, Population Trends 111 available at: http://www.statistics.gov.uk/ statbase/product.asp?vlnk=633 16 Office for (7) Information about the latest NSCD work programme available at: http://www.statistics.gov.uk/ about/data/methodology/specific/population/default.asp 17 Report of the inter-departmental Task Force into international migration statistics, issued December 6. Available at: http://www. statistics.gov.uk/statbase/product.asp?vlnk=14731 18 Office for (7) Interim report on the port survey review, issued October 7. Available at: http://www.statistics.gov. uk/about/data/methodology/specific/population/future/imps/updates/ downloads/psreview.pdf 19 Office for (7). Latest information on the development of the 11 Census available at: http://www.statistics. gov.uk/census/11census/news/default.asp 21