Year Percent 1950 29.66742 1955 28.97687 1960 27.64174 1965 27.54457 1970 27.16986 1975 30.0868 1980 32.7638 1985 32.29669 1990 31.35488 1995 31.07098 2000 30.91632 2005 31.08668 2010 32.54798 2015 32.99861 2020 30.3881 2025 27.68494 2030 26.0146 2035 24.81955 2040 23.76008 2045 22.74679 2050 21.66632 2055 20.90876 2060 20.4781 2065 20.38794 2070 20.37738 2075 20.31616 2080 20.18144 2085 20.05483 2090 20.01341 2095 20.04468 2100 20.09184