Year Percent 1950 32.97569 1955 31.59048 1960 28.80883 1965 26.45384 1970 24.97361 1975 25.80643 1980 27.476 1985 29.14177 1990 31.05866 1995 32.08131 2000 33.02117 2005 33.55339 2010 32.71121 2015 32.16361 2020 32.21053 2025 32.64163 2030 32.48563 2035 31.5775 2040 30.38371 2045 28.93692 2050 28.21419 2055 28.00889 2060 27.72223 2065 27.22178 2070 26.6172 2075 26.12632 2080 25.85499 2085 25.77883 2090 25.74497 2095 25.62555 2100 25.40391