Year Percent 1950 4.68974 1955 5.78719 1960 6.53786 1965 7.95979 1970 9.46306 1975 11.63623 1980 11.18197 1985 10.06576 1990 11.05117 1995 11.71035 2000 13.04385 2005 13.49471 2010 15.55309 2015 18.06232 2020 20.97864 2025 23.65557 2030 25.48026 2035 26.95625 2040 27.64507 2045 28.15618 2050 28.28428 2055 28.49345 2060 28.76992 2065 29.40755 2070 30.07169 2075 30.75008 2080 31.38988 2085 31.96403 2090 32.44813 2095 32.87096 2100 33.2623