Year Percent 1950 18.1379 1955 18.83958 1960 18.47259 1965 18.37763 1970 18.10204 1975 18.51798 1980 18.89804 1985 19.61767 1990 20.68482 1995 22.2056 2000 23.80922 2005 24.57731 2010 24.32764 2015 24.49109 2020 25.59399 2025 26.5644 2030 27.91402 2035 28.80074 2040 29.1908 2045 28.95369 2050 27.83005 2055 26.83961 2060 25.68965 2065 24.61438 2070 23.96939 2075 23.38412 2080 23.09552 2085 23.11196 2090 23.16333 2095 23.10193 2100 22.9014