Measure of ageing population

Measure of ageing population

The median age:  The age at which exactly the population into two numerically equal groups , that is ,half the people are younger

Than this age and half are older

The median age of the Nepalese population I 2005 was estimated population of Nepal is younger. The  population of country may be described as young population of country  of may   be described as young ,intermediated or old on the basics of median age.

Contribution of fertility , mortality and immigration  to change in age structure

Changes in the age structure of the national population distribution reflect the past trends in fertility and mortality . They also reflect the of migration where international migration is significant.

Decline in Fertility  : The reduces the number of birth and its continuity results into declining proportion of children with lowering the numbers in the age structure of the population in the long run , The declining fertility levels are unlikely to rise again to the high levels common until recently are likely to become rare over the course of the twenty first century

Decline mortality in old age group : Contributes an increase in the number of the elder people .Even among the elder people age  structure the oldest- old increase  due to decreasing mortality  rates in group.

Along with fertility and mortality , migration is a component of population change . The international (immigration and emigration) change to number of people and the age structure of the population of a country .