Year Percent 1950 28.9268 1955 29.50577 1960 29.71792 1965 28.90931 1970 27.21796 1975 26.5733 1980 27.31903 1985 28.97903 1990 31.43194 1995 33.34571 2000 34.42507 2005 33.97496 2010 33.54791 2015 32.42476 2020 31.39421 2025 30.59874 2030 30.04987 2035 29.87181 2040 29.51134 2045 28.80291 2050 28.14454 2055 27.29893 2060 26.70798 2065 26.25904 2070 25.83879 2075 25.37153 2080 24.87775 2085 24.42689 2090 24.06548 2095 23.78403 2100 23.54383