Select different countries from the menu to view their international migrant population over time (by decade from 1960 onwards and in 2015). While the charts do not reflect changes in the migrant share of the total population, this information is provided by hovering the cursor over data points within the chart. Immigrant populations can also be disaggregated through the population menu.
1) Because governments collect statistics on international migrants residing within their countries' boundaries in varying ways, there is no consistent cross-country definition of this population. The UN Population Division provides the mid-year estimate of international migrants based on official statistics on the foreign born, i.e., people born outside of the country of current residence. However, for countries that do not collect data on place of birth but have data on citizenship, the estimated number of noncitizens is used instead. In both cases, migrant stock also includes refugees, some of whom may not be foreign born. Most of the data were obtained from population censuses; population registers and nationally representative surveys were also used for information on the number and composition of international migrants. For more information on the UN Population Division’s methodology to estimate the size of international migrants, click here: http://www.un.org/en/development/desa/population/migration/data/estimates2/docs/MigrationStockDocumentation_2015.pdf.
2) Changes in countries' geographic and political boundaries over time affect the size of the total and international migrant populations as well as countries' rankings in the chart above. For example, part of the increase in the world international migrant stock observed between 1980 and 2000 was due to the break-up of the former Soviet Union into 15 independent countries. Because of the changed political boundaries, about 27 million persons were "added" to the 2000 world total international migrant stock. Thus, a person born in the Soviet Republic of Ukraine but residing in Russia was counted as an "internal migrant" during the Soviet Union time and as an "international migrant" after the Soviet Union's dissolution.
3) The UN Population Division may base their population estimates on projections from national-level data collected in earlier years.
Migration Policy Institute tabulation of data from the United Nations, Department of Economic and Social Affairs (2015), Trends in International Migrant Stock: Migrants by Destination and Origin (United Nations database, POP/DB/MIG/Stock/Rev.2015). Available here: http://www.un.org/en/development/desa/population/migration/data/estimates2/estimates15.shtml.