Since 2002, statistics on the population structure by citizenship and country of birth have been based on the data of the Central Residence Register, although other administrative data sources are also used for quality assurance purposes within the framework of the Register-based Census and the Register-based Labour Market Statistics. Those persons are counted who are continuously registered with a main residence in Austria for more than 90 days around the reference date. Before 2002, population data was collected within the framework of censuses. For the inter-censal period annual estimates were calculated for the population. These results are only available for domestic and foreign citizens and not for individual nationalities.
The country of birth corresponds to the state or territory in which the place of birth is located in today's borders, regardless of the country in which the place of birth was located at the time of birth of the person in question.