Year Percent 1950 9.8367 1955 9.84018 1960 9.9152 1965 10.61633 1970 10.01634 1975 11.377 1980 11.8372 1985 10.60129 1990 9.00916 1995 9.42839 2000 9.88062 2005 9.81808 2010 9.22255 2015 8.43273 2020 7.35569 2025 7.06429 2030 6.64071 2035 6.29758 2040 5.92345 2045 5.61565 2050 5.37195 2055 5.18862 2060 5.07994 2065 4.99184 2070 4.91537 2075 4.84269 2080 4.80451 2085 4.78844 2090 4.79045 2095 4.79763 2100 4.79314