Year Percent 1950 18.74728 1955 18.30031 1960 17.39819 1965 16.36628 1970 15.21323 1975 14.38792 1980 13.855 1985 13.76085 1990 13.49232 1995 13.09651 2000 12.88107 2005 12.81664 2010 13.02716 2015 13.38938 2020 13.8037 2025 14.2575 2030 14.81582 2035 15.53596 2040 16.33248 2045 17.15974 2050 18.03664 2055 18.87857 2060 19.64444 2065 20.35842 2070 20.99047 2075 21.55986 2080 22.10387 2085 22.59101 2090 23.01783 2095 23.39671 2100 23.72497