DESA, Department of Economic and Social Affairs
United Nations, 2009

Slow population growth brought about by reductions in fertility leads to population ageing, that is, it produces populations where the proportion of older persons increases while that of younger persons decreases. Population ageing is less advanced in developing countries. Nevertheless, the populations of a majority of them are poised to enter a period of rapid population ageing. Globally, the number of persons aged 60 or over is expected almost to triple, increasing from 739 million in 2009 to 2 billion by 2050. In ageing populations, the numbers of persons with older ages grow faster the higher the age range considered. Thus, whereas the number of persons aged 60 or over is expected to triple, that of persons aged 80 or over (the oldest-old) is projected to increase four-fold. Although the population of all countries is expected to age over the foreseeable future, the population will remain relatively young in countries where fertility is still high. In sharp contrast, the populations of 45 countries or areas are expected to decrease between 2010 and 2050. These countries include Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cuba, Georgia, Germany, Hungary, Japan, Latvia, Lithuania, Moldova, Poland, the Republic of Korea, Romania, the Russian Federation and Ukraine, all of which are expected to see their populations decline by at least 10 per cent by 2050.