Year Percent 1950 24.49451 1955 26.4855 1960 27.96341 1965 27.78202 1970 27.28743 1975 25.60192 1980 22.86778 1985 24.33525 1990 25.53869 1995 30.84683 2000 31.80553 2005 32.71073 2010 32.2148 2015 31.63384 2020 31.51152 2025 31.00508 2030 30.88475 2035 31.10558 2040 30.89385 2045 30.43028 2050 29.61992 2055 28.66646 2060 28.02008 2065 27.4943 2070 26.93949 2075 26.22666 2080 25.38751 2085 24.5519 2090 23.8493 2095 23.31819 2100 22.87828