Year Percent 1950 18.22968 1955 20.27218 1960 19.27461 1965 18.37153 1970 17.51701 1975 16.80224 1980 16.37264 1985 15.82988 1990 15.45851 1995 14.63427 2000 14.01387 2005 13.49526 2010 11.86509 2015 11.45156 2020 10.97769 2025 10.44844 2030 9.9329 2035 9.45529 2040 9.00091 2045 8.59034 2050 8.21784 2055 7.85031 2060 7.48777 2065 7.16702 2070 6.88107 2075 6.63264 2080 6.40931 2085 6.20667 2090 6.02298 2095 5.85587 2100 5.7044