The Statistics on Acquisition of Spanish Citizenship of Residents provides the number of persons who usually reside in Spain and who obtain Spanish nationality during the reference year, having previously held the nationality of another country or statelessness. This operation is based on the statistical treatment of registration of national records in the Civil Register, and completes the set of demographic information that ensures total consistency between population numbers and demographic events (births, deaths, migration and nationalization) and allows the correct classification of information in terms of the country of nationality.