Year Percent 1950 3.98111 1955 3.80724 1960 3.71229 1965 3.68819 1970 3.70172 1975 3.7753 1980 3.92126 1985 4.17678 1990 4.76373 1995 5.30797 2000 5.74289 2005 5.88771 2010 6.42975 2015 7.04755 2020 8.33741 2025 9.66736 2030 11.85872 2035 14.04466 2040 17.2868 2045 21.54614 2050 25.2084 2055 28.07096 2060 30.11178 2065 31.52571 2070 32.75591 2075 33.65079 2080 34.53713 2085 35.26657 2090 35.79696 2095 36.14306 2100 36.39332