Year Percent 1950 4.30311 1955 4.29884 1960 4.34046 1965 4.25893 1970 4.21709 1975 4.18527 1980 4.16522 1985 4.25207 1990 4.42064 1995 4.40499 2000 4.37978 2005 4.33277 2010 4.29556 2015 4.21333 2020 4.24519 2025 4.34588 2030 4.51049 2035 4.82335 2040 5.24418 2045 5.69271 2050 6.09627 2055 6.50046 2060 7.02579 2065 7.75034 2070 8.6267 2075 9.61107 2080 10.58572 2085 11.58199 2090 12.62083 2095 13.7205 2100 14.86249