Year Percent 1950 18.4462 1955 17.72115 1960 17.30671 1965 16.94617 1970 16.54275 1975 16.43022 1980 15.85469 1985 15.22057 1990 14.51788 1995 14.4013 2000 13.68515 2005 13.02849 2010 13.15986 2015 13.09558 2020 12.54387 2025 12.13915 2030 13.47933 2035 16.19758 2040 18.94381 2045 20.72835 2050 21.71549 2055 22.05911 2060 22.25063 2065 22.72359 2070 23.1508 2075 23.621 2080 24.01545 2085 24.34229 2090 24.61047 2095 24.81954 2100 24.95903