Year Percent 1950 4.84388 1955 4.23259 1960 3.99688 1965 3.9116 1970 3.86937 1975 3.9067 1980 4.0449 1985 4.17622 1990 4.51437 1995 4.62327 2000 4.65541 2005 4.49651 2010 4.22164 2015 4.10393 2020 4.0519 2025 4.146 2030 4.39818 2035 4.8441 2040 5.45807 2045 6.29515 2050 7.16126 2055 8.00293 2060 8.81664 2065 9.72324 2070 10.87356 2075 12.21384 2080 13.49025 2085 14.7081 2090 15.92358 2095 17.18306 2100 18.51231