Year Percent 1950 4.60863 1955 4.47879 1960 4.74929 1965 5.17395 1970 5.47364 1975 5.70196 1980 5.68825 1985 5.46377 1990 5.72009 1995 5.69417 2000 5.77906 2005 5.92448 2010 5.93727 2015 6.45457 2020 7.05825 2025 7.81419 2030 8.56469 2035 9.20724 2040 10.35705 2045 12.27721 2050 14.16059 2055 15.84666 2060 17.37404 2065 18.64703 2070 19.82825 2075 20.8387 2080 21.8358 2085 22.77406 2090 23.63324 2095 24.4243 2100 25.16827