Year Percent 1950 41.94887 1955 44.91134 1960 49.68062 1965 45.34314 1970 38.19382 1975 33.76146 1980 38.03992 1985 40.06381 1990 41.6359 1995 45.60306 2000 41.1379 2005 46.42845 2010 46.80015 2015 40.30381 2020 37.45229 2025 36.03125 2030 35.83707 2035 35.22 2040 34.11989 2045 33.444 2050 32.61698 2055 31.71941 2060 30.81468 2065 30.28951 2070 29.87567 2075 29.30741 2080 28.55159 2085 27.71219 2090 26.94308 2095 26.34855 2100 25.89228