Population aging has changed America over the last century and demographic structure. Population aging is an increase in the median age of the country due to rising life expectancy and decreased birth rates. Demography is based on the size, composition and distribution of population. Within the United States population the median age was seventeen in eighteen twenty and by two thousand it increased by thirty five years. Also, the older population continues to grow by twenty thirty the median age is expected to increase by forty two years. The increase in aging population has contribute to major factors such as decline in birth rates, improvement in life expectancy and birth cohorts. A major factor driving population aging is the decline in
