Year Percent 1950 11.4408 1955 11.24424 1960 11.21779 1965 11.47632 1970 11.96769 1975 12.56424 1980 13.05665 1985 13.13275 1990 13.49383 1995 14.34145 2000 15.74068 2005 17.47568 2010 18.99586 2015 20.14336 2020 20.97654 2025 21.81713 2030 22.60868 2035 23.39277 2040 23.89931 2045 24.33195 2050 24.72363 2055 24.97981 2060 25.21897 2065 25.14012 2070 24.86752 2075 24.47853 2080 24.07892 2085 23.68086 2090 23.28144 2095 22.89192 2100 22.53711