Year Percent 1950 28.17437 1955 29.09635 1960 29.66272 1965 29.27902 1970 27.76003 1975 26.89575 1980 27.4027 1985 28.82336 1990 31.1369 1995 33.09398 2000 34.1494 2005 33.903 2010 33.63308 2015 32.41753 2020 31.16771 2025 30.09808 2030 29.46168 2035 29.21659 2040 28.8478 2045 28.14684 2050 27.43717 2055 26.55739 2060 25.93982 2065 25.47255 2070 25.04264 2075 24.57202 2080 24.07735 2085 23.62674 2090 23.26986 2095 23.00199 2100 22.78366