Year Percent 1950 14.07815 1955 13.83511 1960 13.24905 1965 12.75521 1970 11.97218 1975 11.81541 1980 11.91836 1985 12.17783 1990 12.72132 1995 14.02946 2000 15.30393 2005 16.48202 2010 18.31574 2015 19.07363 2020 19.63763 2025 20.08326 2030 20.69764 2035 21.82003 2040 22.79892 2045 23.54749 2050 24.08222 2055 24.32598 2060 24.61826 2065 25.01276 2070 25.33377 2075 25.52352 2080 25.6046 2085 25.6236 2090 25.59739 2095 25.51449 2100 25.37052