Year Percent 1950 30.92815 1955 27.46264 1960 22.61862 1965 20.42885 1970 22.32131 1975 26.85676 1980 30.49445 1985 35.73111 1990 37.61421 1995 36.30759 2000 32.1865 2005 30.26769 2010 28.33012 2015 26.57796 2020 25.51474 2025 24.88433 2030 24.70126 2035 24.58442 2040 24.57878 2045 24.34144 2050 24.14492 2055 23.94975 2060 23.76808 2065 23.59934 2070 23.42763 2075 23.24691 2080 23.03623 2085 22.82449 2090 22.63792 2095 22.48902 2100 22.37701