Year Percent 1950 27.4128 1955 27.39378 1960 24.16772 1965 21.49294 1970 20.65392 1975 21.6201 1980 26.0851 1985 27.78208 1990 27.59693 1995 27.68008 2000 27.73748 2005 29.77822 2010 32.01998 2015 31.26208 2020 29.38901 2025 27.30031 2030 26.03864 2035 26.27707 2040 26.51289 2045 25.75933 2050 24.3532 2055 23.53024 2060 23.30117 2065 23.64443 2070 24.03456 2075 24.07427 2080 23.75466 2085 23.28384 2090 22.96265 2095 22.89657 2100 22.96431