Year Percent 1950 17.56607 1955 16.32365 1960 16.71242 1965 17.48709 1970 19.3941 1975 20.51264 1980 21.81433 1985 22.16612 1990 22.1917 1995 20.22972 2000 17.77109 2005 16.47759 2010 15.74062 2015 15.08695 2020 13.96525 2025 12.77558 2030 11.70496 2035 10.79676 2040 9.98007 2045 9.23981 2050 8.55596 2055 7.89275 2060 7.31353 2065 6.84599 2070 6.46729 2075 6.17297 2080 5.94174 2085 5.75262 2090 5.59834 2095 5.47435 2100 5.37885