Year Percent 1950 13.92569 1955 14.2398 1960 13.6132 1965 13.66932 1970 13.63173 1975 14.60767 1980 17.63086 1985 20.18702 1990 21.5819 1995 20.28863 2000 21.58519 2005 22.04086 2010 25.42572 2015 29.69834 2020 28.40456 2025 28.46636 2030 26.6832 2035 25.6723 2040 26.78817 2045 27.01294 2050 26.6147 2055 25.77535 2060 25.2833 2065 25.09552 2070 25.30261 2075 25.29963 2080 24.88178 2085 24.27493 2090 23.81396 2095 23.65282 2100 23.68395