Based on estimates from the UN Population Division for the international migrant population by country of origin and destination, this map provides the size of either the immigrant or emigrant population by country. Population bubbles are colored according to whether the country has a greater immigrant or emigrant population.
2) 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 (2013). Trends in International Migrant Stock: Migrants by Origin and Destination, 2013 Revision (United Nations database, POP/DB/MIG/Stock/Rev.2013). Available here: http://esa.un.org/unmigration/TIMSO2013/migrantstocks2013.htm.