Year Percent 1950 8.70116 1955 8.74343 1960 9.4587 1965 10.87795 1970 12.59156 1975 13.86165 1980 13.18024 1985 14.5038 1990 17.61022 1995 19.34648 2000 19.73635 2005 20.22553 2010 21.94157 2015 23.37277 2020 24.39556 2025 25.29907 2030 26.32872 2035 28.18607 2040 30.2346 2045 31.5873 2050 33.12226 2055 33.33598 2060 32.09102 2065 31.24964 2070 31.48363 2075 31.76731 2080 32.26283 2085 32.82095 2090 33.2099 2095 33.42412 2100 33.72974