The phenomenon occurs when the median age of the region or the country rises due to the declining fertility rates and rising life expectancy. It is the shift in the distribution of the population of the different countries towards the older age. It usually reflect the increase in the population median or the mean age rise in the proportion of the population that is elderly and a decline in the proportion of the population composed of children. It is the process of becoming older; in the narrow sense this term refer to the aging of the human beings and the other organisms including the animals.
Population Aging in United Stare:
Like the rest of the world, this country is an aging society. This country place the additional substantial pressure on the publicly funded health and the other income support programs for the people of the older age. That is the reason that in this country people spend large portion of their incomes on the health care. Between from 2000 to 2050 large number of people is projected by the increase of 135% the age of the population of this country is 85 and over, which is the sector that likely need long-term health care is projected with the 350% increase. With passing the time large portion of the population that is over the age in 2000 with the increase of 65 from 12.7 percent in this year to 20.3% in the 2050.
An important portion of the population of this country is elderly, Europe also have the large portion of the elder people that are over the age of 65 years. For example in 2000 in United Kingdom about 16.0 % of the population and about 16.4% population of Germany is over the age of 65. Other countries have the cope with the impact of the aging society greater than the united State. (Joshua M Wiener, 2002)