Revised annual mid-year population estimates, UK: 2001 to 2010

• The rebased population of the UK was estimated to be 62.8 million in mid-2010, up from the previously estimated figure of 62.3 million which was based on rolling forward the results of the 2001 Census. This represents a difference of 497,500 (0.8%) over the previous series estimates.
• The rebased estimated populations of the four constituent countries of the UK in mid-2010 were 52.6 million people in England, 5.3 million in Scotland, 3.0 million in Wales and 1.8 million in Northern Ireland.
• The population of the UK aged 65 and over increased by 0.9 million between mid-2001 and mid-2010. The population in this age group represented 16.4% of the total UK population in mid-2010, up from 15.9% in mid-2001. The fastest period of growth in this increase was between mid-2009 and mid-2010.
• The population increase of the UK in the period mid-2001 to mid-2010 was caused by there being 1.4 million more births than deaths (38% of the increase) and 2.1 million more international migrants arriving than emigrants leaving (56% of the increase).
• Over the period mid-2001 to mid-2010 the rebased estimated flow of international migrants to the UK was highest in the year to mid-2007 at 685,500. The highest estimated outflow for the period was during the year to mid-2009 at 407,500 emigrants.

This bulletin presents the main messages shown by the revised 2001 to 2010 mid-year population estimates for the United Kingdom (UK), undertaken to align with the results of the 2011 Census. It provides information on the changing size and age structure of the population of the UK over this period and presents a consistent time series of population estimates for England, Scotland, Wales and Northern Ireland. Accompanying data is provided covering the period mid-2001 to mid-2012 including already published population estimates for mid-2011 and mid-2012. This bulletin has been updated to provide appropriate explanatory background information about the treatment of Northern Ireland migration data.

The mid-year estimates for mid-2001 to mid-2010, all published prior to 2012, have been adjusted to bring them into line with the official mid-2011 population estimates published earlier this year. These rebased mid-year estimates provide a time series of the population on 30 June of each year in the period. They are the official set of population estimates for the UK and its constituent countries, the regions of England and Wales and local authorities for this period. This publication relates to rebased mid-2001 to mid-2010 estimates of the UK and is collated from the estimates produced by the Office for National Statistics (ONS) for England and Wales, the Northern Ireland Statistics and Research Agency (NISRA) for Northern Ireland, and the National Records of Scotland (NRS) for Scotland. The timetables for population outputs are available for each country on their respective websites.

The official rebased mid-year estimates for the UK referred to in this bulletin build on the 2011 census based mid-year estimates that were published on 8 August 2013. The mid-2001 to mid-2010 estimates have been updated to account for the differences observed between the former 2001 Census based series at mid-2011 and the 2011 Census based estimates. Population estimates for mid-2011 and mid-2012 have already been published and are used in this bulletin to put the estimates for mid-2001 to mid-2010 in context.

The rebased mid-year population estimates relate to the usually resident population. They account for long-term international migrants (people who change their country of usual residence for a period of 12 months or more) but do not account for short-term migrants (people who come to or leave the country for a period of less than 12 months).

The mid-year population estimates are essential building blocks for a wide range of National Statistics. They are used directly as a base for other secondary population statistics, such as population projections, population estimates for the very old and population estimates for small geographical areas. They are used for weighting survey estimates such as the Labour Force Survey and other social surveys to ensure that they are representative of the total population, and they are used as denominators for rates or ratios, for example in health and economic indicators. They are an important input for a wide number of economic and social statistics. Main users include central and local government and the health sector, where they are used for planning and monitoring service delivery, resource allocation and managing the economy. Additionally, they are used by a wider range of organisations such as commercial companies (for market research), special interest groups and academia as well as being of interest to the general public.

Further information on population estimates across the UK including methodology, quality and data sources is available in an information note (100.8 Kb Pdf).

The rebased mid-year population estimates series provide estimates of the size and composition of the UK population that are consistent with the results of the 2011 Census.

The population of the United Kingdom in mid-2010

The rebased estimate of the usual resident population of the UK in mid-2010 was 62,759,500. This was comprised of 52,642,500 in England, 5,262,200 in Scotland, 3,050,000 in Wales and 1,804,800 in Northern Ireland.

Figure 1 below shows the distribution of the estimated population between the four constituent countries of the UK for the entire period from mid-2001 to the latest available estimates at mid-2012.

The estimated usual resident population of the UK increased by 3.6 million (6.2%) between mid-2001 and the year ending 30 June 2010; by 3.19 million (6.5%) in England, 198,000 (3.9%) in Scotland, 139,700 (4.8%) in Wales and 116,000 (6.9%) in Northern Ireland.

Annual population growth rates among the countries of the UK for the period since mid-2001 range from a high of 1.1% for Northern Ireland in the year to mid-2007 to only just above zero for Scotland in the year to mid-2002. Figure 2 shows the annual population change in more detail for the countries of the UK during the period.

The rebased estimates show that the population of the UK within the period increased at its fastest in the year to mid-2008 with a growth of some 504,700 (0.8%) people. This growth has since been surpassed by the growth in the year to mid-2011 where a there was an increase of 525,700 (0.8%).

The annual change in the population of the UK by broad contributing reason is given in Figure 3.

The contribution of net international migration to population change over the period can be clearly seen in Figure 3, making up more than half of population growth in the years ending mid-2002 to mid-2008. From mid-2009 to mid-2011 the contribution to population growth of net international migration and natural change - the balance of births minus deaths - was broadly equal.

The balance of births minus deaths has increased year on year over the period, and from contributing slightly more than 24% of population growth in the year ending mid-2002 contributed 49% of population growth in the year ending mid-2010. The latest estimates available show that in the year to mid-2012 the number of births was at a 40 year high.

It should be noted that the two net figures are not independent over time, as past immigrants contribute to the number of births and deaths in subsequent years.

The population estimates described in this bulletin reflect the rebased populations as at 30 June mid-2001 annually to 30 June 2010 and include an estimate of the population change which occurred throughout this period. This series reflects the results of the three UK censuses performed in 2011. This release allows a consistent view of change at UK level to be made, including that between mid-2010 and mid-2011. For completeness and ease of reference population estimates for the UK for mid-2011 and mid-2012 are included in accompanying data.

Mid-year population estimates are derived through a process where the resident population is aged on, those born during the 12 month period are added to the population and those who have died are removed. The estimates take into account the movement of people coming to live in the UK and those leaving to live abroad (international migrants). On a regional level they also account for the movement of people between different areas of the UK (internal migrants). Internal migration includes both cross-border moves between the four countries of the UK and moves between local areas within each country. Details of the methods used to create the estimates of the UK are available in a separate information note (100.8 Kb Pdf).

More detail on the main components of population change over the period mid-2001 to mid-2010 is available in Table 1. There was a total of 6.6 million births and 5.2 million deaths during the nine year period, resulting in a population increase of approximately 1.4 million due to natural change - the balance of births minus deaths. Over the same period 5.4 million international migrants arrived in the UK and 3.3 million international migrants left the UK to live abroad. All of these changes combined resulted in a net increase in population of 3.6 million.

This revised mid-2001 to mid-2010 release for the UK is the sixth ONS population estimates product to be published based on the results of the 2011 Census. Future releases of UK population estimates and projections in 2014 include:

• March 2014: National Population Projections - 2012-based reference volume: Series PP2;

• March 2014: Revised Small Area Population Estimates for the period 2001-2010 – Northern Ireland;

• March 2014: National Park Population Estimates (experimental) England and Wales- Mid-2002 to Mid-2010 revised;

• March-April 2014: Population Projections for Scottish Areas - 2012 based Sub-National Population Projections;

• Spring 2014: 2012-based population projections for areas within Northern Ireland;

• April 2014: Mid-2013 Population Estimates Scotland;

• May 2014: Population Projections for Scottish Areas - 2012 based Sub-National Population Projections;

• May-June 2014: Sub-national population projections - 2012-based projections – England; and

• June 2014: Population Estimates for UK, England and Wales, Scotland and Northern Ireland - Mid-2013.

Dates given here are provisional. Any changes or confirmation of dates will be announced on the UK statistics Publication Hub release calendar.