Year Percent 1950 30.69805 1955 30.6969 1960 30.63816 1965 29.56634 1970 28.48783 1975 26.91311 1980 26.99861 1985 27.75183 1990 28.03148 1995 29.00554 2000 29.82489 2005 29.08552 2010 29.31122 2015 29.40316 2020 29.13655 2025 29.09994 2030 28.50517 2035 27.4213 2040 26.54114 2045 25.88954 2050 25.29825 2055 24.72325 2060 24.10921 2065 23.51603 2070 23.00714 2075 22.61631 2080 22.32586 2085 22.08794 2090 21.8676 2095 21.65057 2100 21.45773