Year Percent 1950 15.12661 1955 17.27643 1960 18.50148 1965 19.40025 1970 20.73183 1975 20.69581 1980 19.78378 1985 18.80607 1990 19.99971 1995 23.12096 2000 27.29258 2005 32.80705 2010 33.58896 2015 33.22523 2020 31.1866 2025 29.57347 2030 28.6562 2035 27.87992 2040 26.13753 2045 23.13188 2050 21.20554 2055 19.78564 2060 20.23704 2065 22.04111 2070 23.27586 2075 23.72137 2080 23.01779 2085 22.03364 2090 21.33223 2095 21.46986 2100 22.04541