Year Percent 1950 14.54549 1955 15.20315 1960 13.84018 1965 14.40502 1970 14.9467 1975 15.19914 1980 15.0014 1985 14.72584 1990 14.48608 1995 14.29346 2000 13.88349 2005 13.80233 2010 13.31908 2015 13.20678 2020 13.14591 2025 12.38636 2030 11.65743 2035 11.098 2040 10.71289 2045 10.37917 2050 10.06535 2055 9.69223 2060 9.27356 2065 8.89545 2070 8.58608 2075 8.30816 2080 8.0357 2085 7.75701 2090 7.48512 2095 7.21804 2100 6.98477