The present report is based on the results of the thirteenth round of population estimates and projections; the 1992 revision. This volume contains estimates and projections that present the sex and age distribution of national populations and aggregations among the world’s countries and regions for the period 1950- 1990. It also contains projected figures according to medium- high and low-fertility variants for 1990-2025. Most estimates presented are derived from available national data that have been evaluated and, whenever necessary, adjusted for deficiencies and inconsistencies.