Year Percent 1950 13.76429 1955 14.17093 1960 14.56788 1965 14.39888 1970 14.40486 1975 14.41106 1980 12.10635 1985 13.00101 1990 13.66226 1995 14.26227 2000 12.54397 2005 12.09626 2010 13.60468 2015 14.01462 2020 12.46281 2025 12.11463 2030 11.46756 2035 11.50652 2040 14.24439 2045 15.66101 2050 17.60388 2055 19.29736 2060 19.92902 2065 21.08558 2070 22.04436 2075 22.85219 2080 23.59294 2085 24.0866 2090 24.35054 2095 24.52317 2100 24.66619