Year Percent 1950 9.55995 1955 10.32553 1960 11.14073 1965 12.06393 1970 12.96398 1975 14.07471 1980 13.21255 1985 14.34849 1990 17.62438 1995 19.51751 2000 21.66491 2005 22.30913 2010 24.29444 2015 27.05303 2020 29.1258 2025 29.33809 2030 31.72497 2035 33.86696 2040 36.13247 2045 36.87948 2050 38.44624 2055 38.58732 2060 38.45896 2065 38.19922 2070 38.20437 2075 38.00779 2080 37.88886 2085 37.85504 2090 37.86342 2095 37.96259 2100 38.16833