Figures used in this chart are based on the most up to date estimate or projections by the national census authority where available, and are usually rounded off. Where updated national data are not available, figures are based on the 2013 estimates by the Population Division of the United Nations Department of Economic and Social Affairs. Because the compiled figures are not collected at the same time in every country, or at the same level of accuracy, the resulting numerical comparisons may create misleading conclusions. Furthermore, the addition of figures from all countries may not equal the world total.