Eurostat disseminates the population data as transmitted by the countries in accordance with the Article 3 of Regulation (EU) No 1260/2013 on European demographic statistic and Article 3 of Regulation (EU) No 862/2007 on Community statistics on migration and international protection.

Population data are transmitted as data on 31 December of the year T and then published by Eurostat as Population on 1 January of year T+1. The population datasets available at national level have various disaggregation; as follows: by age; sex; country of birth; country of citizenship; group of country of birth; group of country citizenship and level of human development of the country (of birth and of citizenship).

Citizenship is defined as the particular legal bond between an individual and his/her State; acquired by birth or naturalization; whether by declaration; choice; marriage or other means according to national legislation.

Country of birth is defined as the country of residence (in its current borders; if the information is available) of the mother at the time of the birth or; in default; the country (in its current borders; if the information is available) in which the birth took place.

Level of development is defined as the relative degree of development of a country as defined by statistical measures of three basis dimensions - health; education and standard of living.