Year Percent 1950 5.24244 1955 4.75755 1960 4.41647 1965 4.28758 1970 4.39484 1975 4.48193 1980 4.47096 1985 4.33054 1990 4.40873 1995 4.30526 2000 4.26897 2005 4.19854 2010 4.1231 2015 4.3434 2020 4.73381 2025 5.17273 2030 5.61843 2035 6.09672 2040 6.69845 2045 7.52409 2050 8.42633 2055 9.24519 2060 10.00758 2065 10.78903 2070 11.68395 2075 12.69927 2080 13.66859 2085 14.56345 2090 15.40849 2095 16.25064 2100 17.12625