Year Percent 1950 27.50342 1955 27.42969 1960 27.21379 1965 27.47956 1970 28.08409 1975 29.34312 1980 32.706 1985 36.40302 1990 38.1184 1995 34.95157 2000 35.94566 2005 37.916 2010 38.34106 2015 37.62246 2020 34.87516 2025 32.20278 2030 30.7953 2035 29.68053 2040 29.43727 2045 28.91705 2050 27.85003 2055 26.50986 2060 25.05263 2065 24.16587 2070 23.8747 2075 23.85959 2080 23.74653 2085 23.32776 2090 22.69645 2095 22.13212 2100 21.83241