Year Percent 1950 27.35067 1955 29.68325 1960 32.05858 1965 33.98696 1970 32.78635 1975 28.73369 1980 29.66406 1985 29.08424 1990 31.86858 1995 35.56755 2000 32.98162 2005 32.2136 2010 29.55487 2015 27.7078 2020 28.20002 2025 27.72693 2030 26.6718 2035 25.27901 2040 24.37239 2045 23.83911 2050 23.79295 2055 23.63819 2060 23.16023 2065 22.53819 2070 22.05988 2075 21.86685 2080 21.86691 2085 21.83745 2090 21.63263 2095 21.31281 2100 21.04498