Year Percent 1950 3.45356 1955 3.81408 1960 4.041 1965 4.21398 1970 4.38102 1975 4.46676 1980 4.51282 1985 4.56717 1990 4.88778 1995 4.84925 2000 5.16117 2005 6.39756 2010 7.36104 2015 8.22215 2020 8.65263 2025 9.29234 2030 10.01012 2035 10.91339 2040 11.86383 2045 13.02578 2050 14.6762 2055 17.24561 2060 21.25562 2065 25.43148 2070 28.78634 2075 31.01866 2080 33.04987 2085 34.83766 2090 36.24764 2095 37.1654 2100 37.73538