RENA project principal investigator Dr Kristian Lewis and lead associate Dr Filip Škiljan collected, processed, and systematized statistical data on changes in the number of members of national minorities in Croatia from 1931 to 2021. The statistical data can be searched by year, by individual national minority, and by the share of each national minority in the total number of national minority members over the course of 90 years. The publication of these data represents one of the main project outcomes achieved in the first year of the project. The processed and systematized data were graphically designed by Dr Maja Matijević, whom we sincerely thank for her generous professional and collegial assistance. The data are available at the following link.