Year Percent 1950 2.5764 1955 3.57971 1960 4.3335 1965 4.08319 1970 3.77538 1975 4.18002 1980 4.89128 1985 5.22082 1990 6.43109 1995 7.18758 2000 7.25454 2005 7.3395 2010 6.98138 2015 6.87366 2020 7.62108 2025 8.04655 2030 8.68115 2035 9.60039 2040 9.99248 2045 10.33882 2050 10.46045 2055 11.82099 2060 13.68418 2065 15.93009 2070 18.02819 2075 19.49057 2080 20.44814 2085 21.46144 2090 22.77244 2095 24.35178 2100 25.97501