Components of population change 2011 Census
Population change at a national level occurs as a result of two factors: a difference between the number of births and the number of deaths, and a difference between the number of people migrating into a country and the number migrating out of the country (net migration).
Population change due to births, deaths, net migration and other for England and Wales, revised estimates for mid-2001 to mid-2011
The chart above shows the contribution that the different types of change have made to the population growth in England and Wales since mid-2001 (that is, the contribution that births minus deaths make compared with net migration). The contribution of migration in the rolled-forward series is also shown to illustrate the impact of the revisions. It should be noted though that the contributions of births, deaths and migration are interlinked, as past immigrants contribute to the number of births and deaths in subsequent years.
In the year ending mid-2011, the relative contributions of births minus deaths (239,000) and net migration (235,000) were broadly equal. Prior to mid-2008 migration contributed a larger proportion of the population change in each year than the difference between births and deaths. Between mid-2008 and mid-2009 however, the difference between births and deaths had a larger impact on population change than net migration.
Source Office for National Statistics