Year Percent 1950 30.73037 1955 29.60929 1960 27.11163 1965 24.17526 1970 22.52251 1975 23.33343 1980 25.52421 1985 28.57643 1990 31.00326 1995 32.01635 2000 32.77515 2005 33.55289 2010 34.18395 2015 34.2226 2020 31.95231 2025 28.94381 2030 26.24726 2035 24.2756 2040 24.13983 2045 24.36862 2050 23.87809 2055 22.81501 2060 21.88479 2065 21.25667 2070 21.19222 2075 21.46632 2080 21.59274 2085 21.37632 2090 20.98147 2095 20.66089 2100 20.54053