Year Percent 1950 19.66304 1955 18.83981 1960 16.90006 1965 16.21257 1970 19.02215 1975 21.40702 1980 25.06093 1985 24.14589 1990 21.72774 1995 21.51526 2000 21.83383 2005 24.64282 2010 26.14613 2015 26.7707 2020 26.24505 2025 25.70543 2030 26.60453 2035 26.91149 2040 26.16241 2045 24.79785 2050 24.11662 2055 24.6478 2060 25.64556 2065 26.5356 2070 25.81345 2075 24.2269 2080 23.5006 2085 23.66857 2090 24.16125 2095 24.34147 2100 24.00101