Year Percent 1950 13.78043 1955 13.58446 1960 13.41509 1965 13.26204 1970 12.8457 1975 12.44449 1980 12.0163 1985 11.66625 1990 11.61483 1995 11.84679 2000 11.89928 2005 11.57918 2010 11.58098 2015 11.73061 2020 12.46131 2025 14.35745 2030 17.25126 2035 20.0919 2040 21.97287 2045 22.7521 2050 23.09614 2055 23.60457 2060 24.52658 2065 25.43672 2070 25.8756 2075 25.96462 2080 25.90284 2085 25.90272 2090 25.92787 2095 25.85956 2100 25.63959