Year Percent 1950 9.47905 1955 9.63079 1960 10.3455 1965 11.65673 1970 13.30232 1975 14.58153 1980 14.07201 1985 15.56693 1990 19.26795 1995 21.34951 2000 22.14248 2005 23.0962 2010 25.32182 2015 27.07744 2020 28.28166 2025 29.23246 2030 30.21929 2035 31.93485 2040 33.82169 2045 34.97677 2050 36.43828 2055 36.59111 2060 35.2476 2065 34.20309 2070 34.16824 2075 34.13407 2080 34.30791 2085 34.58866 2090 34.77125 2095 34.84671 2100 35.05126