Year Percent 1950 3.6007 1955 3.89375 1960 4.47513 1965 4.30018 1970 4.36581 1975 4.6938 1980 4.63588 1985 4.65115 1990 5.28091 1995 5.88347 2000 6.77912 2005 7.98239 2010 9.33724 2015 11.1412 2020 13.31618 2025 16.09379 2030 19.07028 2035 21.39495 2040 23.43451 2045 25.19281 2050 26.9894 2055 28.76279 2060 30.44125 2065 31.86761 2070 32.97417 2075 34.30673 2080 35.42826 2085 36.28607 2090 37.02433 2095 37.66535 2100 38.23368