This study reviews the highly diverse regional and country patterns of HIV epidemics and discusses possible causes of the geographic variation in epidemic sizes. Past trends and projections of the epidemics are presented and the peak years of epidemics are estimated. The potential future impact...

Rapid population aging is raising concerns about the sustainability of public pension systems in high-income countries. The first part of this study identifies the four factors that determine trends in public pension expenditures: population aging, pension benefit levels, the mean age at...