Year Percent 1950 6.59881 1955 5.45096 1960 4.74458 1965 4.34352 1970 4.187 1975 4.16877 1980 4.15879 1985 4.12329 1990 4.30277 1995 4.33435 2000 4.22098 2005 4.15813 2010 4.12562 2015 4.22243 2020 4.38578 2025 4.65761 2030 5.06111 2035 5.63024 2040 6.31219 2045 7.00511 2050 7.6576 2055 8.18196 2060 8.74812 2065 9.5557 2070 10.51334 2075 11.42883 2080 12.24915 2085 13.01882 2090 13.80965 2095 14.63344 2100 15.47438