Year Percent 1950 19.05173 1955 16.76413 1960 17.32358 1965 18.03586 1970 18.59343 1975 18.90941 1980 19.16445 1985 19.14219 1990 18.28649 1995 18.26814 2000 17.96016 2005 17.69416 2010 17.60783 2015 16.0981 2020 15.54754 2025 14.88816 2030 14.12864 2035 13.30327 2040 12.52147 2045 11.79657 2050 11.1119 2055 10.48738 2060 9.89604 2065 9.34369 2070 8.8252 2075 8.34082 2080 7.89823 2085 7.49337 2090 7.11453 2095 6.78553 2100 6.49015