Year Percent 1950 26.27896 1955 29.31225 1960 31.60677 1965 31.61502 1970 29.25649 1975 29.96955 1980 30.24042 1985 31.82087 1990 30.9454 1995 30.0397 2000 28.31084 2005 28.26531 2010 27.94248 2015 27.23372 2020 26.38676 2025 24.95935 2030 24.26708 2035 23.41656 2040 22.65798 2045 22.17282 2050 21.51805 2055 21.02652 2060 20.72754 2065 20.5398 2070 20.40827 2075 20.29313 2080 20.15932 2085 20.04505 2090 19.98003 2095 19.95932 2100 19.94568