Year Percent 1950 12.8181 1955 11.5455 1960 9.8453 1965 8.89103 1970 8.44362 1975 8.63096 1980 8.25234 1985 8.46579 1990 11.92008 1995 13.38252 2000 15.58731 2005 15.46093 2010 15.71933 2015 16.74179 2020 17.91851 2025 19.47491 2030 20.32731 2035 21.41397 2040 22.37457 2045 23.27486 2050 24.7074 2055 25.9098 2060 26.21428 2065 26.01873 2070 27.00282 2075 28.84743 2080 30.17235 2085 30.94318 2090 31.36881 2095 31.77616 2100 32.35192