Year Percent 1950 19.10038 1955 20.35036 1960 19.37293 1965 17.49438 1970 16.67053 1975 17.88079 1980 16.82653 1985 15.22669 1990 15.78321 1995 20.02769 2000 26.66953 2005 31.15598 2010 32.99241 2015 32.17582 2020 29.61595 2025 29.26013 2030 30.94618 2035 30.82308 2040 30.00545 2045 25.97297 2050 21.86586 2055 20.4621 2060 21.19722 2065 22.97761 2070 24.06788 2075 23.84752 2080 22.88726 2085 22.14491 2090 21.96034 2095 22.22958 2100 22.53558