Year Percent 1950 27.15255 1955 26.93266 1960 26.55088 1965 26.44805 1970 27.41882 1975 29.24112 1980 32.10395 1985 34.31886 1990 36.03827 1995 36.37525 2000 34.61331 2005 32.28856 2010 30.77494 2015 30.77469 2020 29.75922 2025 30.13184 2030 29.48446 2035 26.9944 2040 25.13363 2045 23.30859 2050 22.69576 2055 22.88015 2060 22.92337 2065 22.5559 2070 21.90796 2075 21.39326 2080 21.26467 2085 21.47313 2090 21.74169 2095 21.80462 2100 21.62794