Forecasting the old?age dependency ratio to determine a sustainable pension age

We forecast the old-age dependency ratio for Australia under various pension age proposals, and estimate a scheme that will provide stable at specified level. Our approach involves stochastic population forecasting method based on coherent functional data models mortality, fertility net migration, which we use to simulate future age-structure of population. results suggest Australian should be increased 68 by 2030, 69 2036 70 2050, in order maintain 23%, just above 2018 general can easily extended other target levels countries.