Year Percent 1950 19.9147 1955 20.77936 1960 19.58073 1965 17.49751 1970 16.71253 1975 18.80936 1980 17.81491 1985 14.97234 1990 14.47688 1995 17.63824 2000 24.39408 2005 29.67479 2010 33.53611 2015 33.80611 2020 31.37279 2025 30.51771 2030 31.58012 2035 30.64326 2040 29.60579 2045 25.36997 2050 20.85797 2055 19.41908 2060 20.20672 2065 22.01311 2070 23.15612 2075 23.0134 2080 22.12195 2085 21.46206 2090 21.35361 2095 21.66392 2100 21.97976