ABSTRACT
The world is graying. Since the twentieth century, developed nations are undergoing a steady process of unprecedented demographic changes due to a decrease in the rate of birth, and a signifi cant increase in life expectancy. In the developed nations, life expectancy has increased by an average of 30 years in less than a century. These developments have caused major transformations in the composition of populations in terms of the proportion of the various age groups. While the young age groups of children and adolescents have decreased, those of elderly persons aged 65 and over, have signifi cantly increased. This relatively rapid global process of change is known as “the process of squaring the former demographic pyramid” or the “demographic revolution.”
