Year Percent 1950 13.27327 1955 13.84389 1960 14.62675 1965 15.68053 1970 16.66186 1975 16.67707 1980 15.55854 1985 15.57713 1990 18.99835 1995 18.99257 2000 18.82697 2005 19.00459 2010 18.95434 2015 19.1269 2020 20.54942 2025 22.4211 2030 24.64482 2035 26.0885 2040 27.03947 2045 28.20396 2050 28.81485 2055 29.22866 2060 29.6595 2065 29.95627 2070 30.18967 2075 30.58893 2080 31.22162 2085 31.90762 2090 32.60105 2095 33.29171 2100 33.97536