Year Percent 1950 8.67152 1955 8.0947 1960 7.87911 1965 7.34184 1970 7.27325 1975 7.30678 1980 7.27798 1985 7.50883 1990 8.8593 1995 9.97087 2000 10.75515 2005 12.29387 2010 15.24378 2015 18.45564 2020 22.11509 2025 25.78151 2030 28.56337 2035 30.94411 2040 33.16029 2045 35.49669 2050 36.4253 2055 37.78826 2060 40.79586 2065 41.83241 2070 41.55034 2075 41.97017 2080 42.41677 2085 42.99874 2090 43.4821 2095 43.57765 2100 43.39468