Year Percent 1950 13.52058 1955 14.43012 1960 15.61841 1965 16.93236 1970 17.86012 1975 18.33496 1980 16.74111 1985 16.69658 1990 20.38044 1995 20.87232 2000 23.31597 2005 24.85131 2010 26.06155 2015 27.34928 2020 29.21637 2025 32.08974 2030 34.69531 2035 35.47946 2040 35.88782 2045 36.66402 2050 37.63554 2055 37.95661 2060 37.91721 2065 37.62689 2070 37.38574 2075 37.38909 2080 37.5766 2085 37.86638 2090 38.15382 2095 38.40472 2100 38.66545