Year Percent 1950 4.63285 1955 4.45549 1960 4.21413 1965 3.89943 1970 3.54901 1975 3.16032 1980 2.85809 1985 3.00944 1990 3.54976 1995 3.45651 2000 3.99989 2005 3.65277 2010 3.63679 2015 4.14179 2020 4.83965 2025 5.87757 2030 6.22901 2035 6.63262 2040 7.43838 2045 8.84378 2050 10.60737 2055 11.55912 2060 12.89284 2065 14.45779 2070 16.32182 2075 18.19635 2080 19.95944 2085 21.5926 2090 23.18542 2095 24.82537 2100 26.4667