Year Percent 1950 28.15418 1955 28.96644 1960 29.75898 1965 30.74326 1970 30.04452 1975 30.04119 1980 31.20566 1985 34.76519 1990 36.33968 1995 40.44318 2000 38.73272 2005 40.75228 2010 43.7589 2015 40.95771 2020 36.06046 2025 31.54786 2030 30.17567 2035 30.161 2040 29.61913 2045 29.18891 2050 28.23469 2055 27.1304 2060 26.24287 2065 26.02621 2070 26.02606 2075 25.85397 2080 25.43156 2085 24.86587 2090 24.36293 2095 24.05405 2100 23.90299