Year Percent 1950 5.79129 1955 5.44254 1960 5.2107 1965 5.05589 1970 4.97489 1975 5.03222 1980 5.29656 1985 5.73745 1990 6.93419 1995 7.68092 2000 8.59297 2005 9.57692 2010 10.64013 2015 11.98202 2020 13.39677 2025 15.00885 2030 16.76523 2035 18.73459 2040 20.84743 2045 22.95444 2050 25.47571 2055 28.81677 2060 32.20624 2065 34.52261 2070 36.38805 2075 38.03451 2080 39.67301 2085 41.04904 2090 42.03459 2095 42.6738 2100 43.11105