in the 21st century, one of the most significant population trends is aging. currently, over 11% of the world's current population are people aged 60 and older and the united nations population fund (unfpa) estimates that by 2050 that number will rise to approximately 22%. aging has occurred due to development which has enabled better nutrition, sanitation, health care, education and economic well-being. consequently, fertility rates have continued to decline and life expectancy has risen. life expectancy at birth is over 80 now in 33 countries. aging is a "global phenomenon", that is occurring fastest in developing countries, including those with large youth populations, and poses social and economic challenges to the work which can be overcome with "the right set of policies to equip individuals, families and societies to address these challenges and to reap its benefits".