Year Percent 1950 27.63954 1955 27.7442 1960 27.40546 1965 26.84293 1970 26.1006 1975 26.70789 1980 28.17508 1985 29.59615 1990 30.78095 1995 31.68438 2000 32.3211 2005 32.75332 2010 32.47929 2015 31.21252 2020 30.21949 2025 29.10203 2030 28.05973 2035 27.27208 2040 26.2494 2045 25.24232 2050 24.26097 2055 23.28067 2060 22.46278 2065 21.86236 2070 21.42344 2075 21.02587 2080 20.65236 2085 20.30014 2090 20.01002 2095 19.81451 2100 19.69396