Year Percent 1950 27.44271 1955 28.2071 1960 29.55958 1965 29.27198 1970 28.22989 1975 27.14246 1980 27.37425 1985 28.41248 1990 29.86854 1995 31.32867 2000 32.53931 2005 33.32856 2010 33.34524 2015 32.34488 2020 31.64657 2025 30.73364 2030 29.80288 2035 29.06823 2040 27.97377 2045 26.85366 2050 25.75868 2055 24.68218 2060 23.80273 2065 23.15902 2070 22.68851 2075 22.2617 2080 21.8614 2085 21.49252 2090 21.19383 2095 21.00175 2100 20.88195