The Yearbook collects, compiles and disseminates official statistics on a wide range of topics. Data have been collected from national statistical authorities since 1948 through a set of questionnaires dispatched annually by the United Nations Statistics Division to over 230 national statistical offices. The Yearbook disseminates statistics on population size and composition, births, deaths, marriage and divorce on an annual basis. This edition presents data as available for reference years up to and including 2019.