The size of the strata in the population was estimated based on several sources. As far as possible the same source (namely EUROSTAT) was used across countries for the sake of homogeneity and comparability. However, in many cases EUROSTAT statistics are not detailed enough for the purposes of the estimation and national sources were used instead. For the full references on Eurostat and national statistics refer to Annex 2. The following tables set out the stratification of the main sample in each country in comparison to the composition of the population. .
