Year Percent 1950 29.17249 1955 30.04037 1960 29.16775 1965 26.80203 1970 23.84789 1975 23.37685 1980 25.2059 1985 27.69227 1990 30.52894 1995 31.23335 2000 31.84677 2005 32.8005 2010 33.04293 2015 32.62898 2020 31.13632 2025 29.12969 2030 27.70671 2035 27.15474 2040 27.05816 2045 26.73909 2050 26.04243 2055 24.72984 2060 23.69037 2065 23.02314 2070 22.63034 2075 22.31186 2080 21.90874 2085 21.4024 2090 20.89767 2095 20.51059 2100 20.26783