Year Percent 1950 4.20658 1955 3.87749 1960 3.866 1965 4.4168 1970 4.85982 1975 5.03539 1980 5.06139 1985 4.79849 1990 4.40252 1995 4.38238 2000 4.29549 2005 4.19382 2010 3.94926 2015 3.90997 2020 3.94148 2025 4.00719 2030 4.20525 2035 4.33397 2040 4.73434 2045 5.23588 2050 5.77322 2055 6.43841 2060 7.30018 2065 8.33309 2070 9.4917 2075 10.75781 2080 12.03124 2085 13.28447 2090 14.50951 2095 15.70395 2100 16.84225