Year Percent 1950 45.53748 1955 45.53085 1960 45.75233 1965 33.7245 1970 21.06564 1975 21.05801 1980 20.18016 1985 21.65622 1990 23.85985 1995 25.35081 2000 28.82927 2005 28.92471 2010 29.78934 2015 29.6628 2020 28.69141 2025 29.8589 2030 30.38572 2035 31.27571 2040 31.58048 2045 31.25775 2050 30.90528 2055 30.68373 2060 30.61854 2065 30.51982 2070 30.28308 2075 29.95241 2080 29.59686 2085 29.25927 2090 28.96968 2095 28.70487 2100 28.4294