Individual countries 2000-2020 UN adjusted. The dataset is available to download in Geotiff format at a resolution of 3 arc (approximately 100m at the equator) . The projection is Geographic Coordinate System, WGS84. The units are number of people per pixel with country totals adjusted to match the corresponding official United Nations population estimates that have been prepared by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2019 Revision of World Population Prospects). The mapping  approach is Random Forest-based dasymetric redistribution. 

The methodology used to estimate the annual subnational census-based figures can be found in Lloyd et al , while the information and sources of the input population data are available here.  Percentage difference between the subnational census-based and UN-based figures in 2010 has been visualised in 2D map.