Year Percent 1950 17.53008 1955 19.55946 1960 19.9103 1965 18.00839 1970 16.35946 1975 15.64987 1980 13.86233 1985 13.91556 1990 15.77599 1995 19.82211 2000 23.72639 2005 26.96282 2010 27.78295 2015 27.85501 2020 26.62822 2025 25.32674 2030 24.24473 2035 23.29871 2040 22.88949 2045 22.79639 2050 23.00331 2055 23.14306 2060 23.26263 2065 23.0681 2070 22.87176 2075 22.66819 2080 22.51266 2085 22.41134 2090 22.359 2095 22.32756 2100 22.27607