Year Percent 1950 28.52155 1955 27.1818 1960 26.35396 1965 24.59598 1970 23.84742 1975 25.65797 1980 27.62426 1985 31.37385 1990 34.39978 1995 34.81465 2000 33.4506 2005 30.1367 2010 27.56347 2015 25.56427 2020 24.3914 2025 24.66774 2030 24.87188 2035 24.91097 2040 24.27399 2045 23.17984 2050 22.5365 2055 22.05625 2060 21.82784 2065 21.55265 2070 21.11018 2075 20.56702 2080 20.0761 2085 19.70934 2090 19.4447 2095 19.2318 2100 19.02411