Year Percent 1950 14.26896 1955 15.22639 1960 16.35335 1965 17.39014 1970 17.87244 1975 17.85912 1980 16.33153 1985 16.60758 1990 20.11713 1995 19.70923 2000 20.5181 2005 22.09519 2010 23.26756 2015 24.31516 2020 26.50402 2025 29.52003 2030 32.41335 2035 33.9825 2040 34.88788 2045 36.21288 2050 37.25313 2055 38.00416 2060 37.8393 2065 37.46068 2070 37.16791 2075 37.0934 2080 37.27165 2085 37.51849 2090 37.74636 2095 37.94501 2100 38.18666