Aging Index = population (over 65) / population (under 15)
Young Dependency Ratio = population (under 15) / population (15 - 64)
Old Dependency Ratio = population (over65) / population (15 - 64)
Dependency Ratio = population (over65) + population (under 15) / population (15 - 64)
Most of towns in Taiwan have increments in Aging Index from 2008 to 2011 , but there are some eastern towns have declines in Aging Index.
Due to the decline in birth rate, the changes in Young Dependency Ratio had all been reduced . However , this does not mean that the pressures of parents in Taiwan had also been reduced , actually , bad economical condition is one of the reason that made the birth rate decline.
Generally speaking, towns in western Taiwan have greater positive changes against towns in eastern Taiwan. LiouChou in PingTung has the largest change ( + 1.24 % ) ,which means either the nubmer of the elderly there has been increasing or the number of people aged 15 - 64 has been declining.
DaHu, MiouLi has dropped the most dependency ratio(5.86%) from 2008 to 2011. And DaAn , Taichung has the least change in dependency ratio throuth those years.