Year Percent 1950 28.90297 1955 28.46266 1960 27.93323 1965 27.49547 1970 27.04911 1975 26.9303 1980 27.34035 1985 26.38037 1990 23.04022 1995 25.87678 2000 25.87785 2005 26.41754 2010 26.89924 2015 27.42409 2020 28.21798 2025 29.165 2030 30.09442 2035 30.74287 2040 31.05836 2045 31.21592 2050 31.34825 2055 31.46118 2060 31.53041 2065 31.44069 2070 31.18293 2075 30.81634 2080 30.40434 2085 29.96753 2090 29.52231 2095 29.05431 2100 28.57948