Year Percent 1950 18.43876 1955 17.95588 1960 18.71514 1965 20.65102 1970 20.80356 1975 20.11872 1980 19.90627 1985 19.30983 1990 19.62413 1995 19.96469 2000 18.13566 2005 16.08987 2010 15.43866 2015 14.98862 2020 14.31903 2025 13.38618 2030 12.41321 2035 11.57329 2040 10.90612 2045 10.34797 2050 9.80866 2055 9.25662 2060 8.70352 2065 8.21091 2070 7.77259 2075 7.39535 2080 7.04864 2085 6.72411 2090 6.42591 2095 6.14683 2100 5.91022