Year Percent 1950 9.40181 1955 9.58713 1960 10.36497 1965 11.45356 1970 13.05883 1975 14.22964 1980 14.62012 1985 15.19022 1990 18.53034 1995 19.02747 2000 19.97685 2005 21.46035 2010 24.7645 2015 27.06761 2020 28.74177 2025 30.21914 2030 31.04871 2035 30.97289 2040 31.17819 2045 31.51364 2050 31.74572 2055 32.39596 2060 32.60852 2065 32.82217 2070 33.37101 2075 33.84518 2080 34.36814 2085 34.88949 2090 35.35914 2095 35.80676 2100 36.30373