Year Percent 1950 14.16981 1955 14.55472 1960 15.0184 1965 15.74674 1970 16.54166 1975 17.28052 1980 17.31426 1985 17.61867 1990 20.8701 1995 20.73756 2000 20.80626 2005 21.23106 2010 22.65864 2015 23.51493 2020 24.76878 2025 26.60829 2030 28.28637 2035 29.22764 2040 29.88631 2045 30.68207 2050 31.49005 2055 32.01581 2060 32.18203 2065 32.15941 2070 32.67579 2075 33.33358 2080 33.96931 2085 34.52863 2090 34.97887 2095 35.4206 2100 35.9539