Year Percent 1950 29.87253 1955 29.76436 1960 29.52692 1965 29.20766 1970 27.9617 1975 26.98531 1980 26.25297 1985 25.78245 1990 26.3035 1995 27.22989 2000 28.0177 2005 28.58302 2010 28.7695 2015 28.6871 2020 29.09339 2025 29.82814 2030 30.57812 2035 31.17446 2040 31.34947 2045 31.23525 2050 31.14038 2055 31.12199 2060 31.04322 2065 30.83098 2070 30.4964 2075 30.10057 2080 29.6747 2085 29.26073 2090 28.83211 2095 28.36907 2100 27.86832