The international migration dataset contains the flows and stocks of the total "immigrant", i.e. foreign-born, population in each country as well as information on acquisition of nationality. These data have not been standardised and are therefore not fully comparable across countries. In particular, the process of registering the foreign-born population and the process of granting residence permission vary across coutries. Furthermore, no statement can be made about the coverage of unautorized migrants in the dataset.
Data is gathered from the OECD International Migration Database.