The data has been compiled by the Inter-Parliamentary Union on the basis of information provided by National Parliaments. Comparative data on the world and regional averages as well as data concerning the two regional parliamentary assemblies elected by direct suffrage can be found on separate pages.

Note: The figures for South Africa on the distribution of seats in the Upper House do not include the 36 special rotating delegates appointed on an ad hoc basis, and all percentages given are therefore calculated on the basis of the 54 permanent seats. Included in the QoG Dataset are the data from latest monthly available data each year.