Year Percent 1950 26.09487 1955 24.5159 1960 23.6755 1965 23.3153 1970 23.99252 1975 26.34026 1980 27.89641 1985 29.01743 1990 29.56279 1995 28.95546 2000 28.88148 2005 30.07188 2010 31.65611 2015 33.40242 2020 34.18781 2025 33.37601 2030 32.22416 2035 31.00793 2040 29.95724 2045 29.45994 2050 28.84163 2055 28.16255 2060 27.31745 2065 26.50427 2070 25.86053 2075 25.37622 2080 24.95183 2085 24.52449 2090 24.06915 2095 23.60634 2100 23.16134