Year Percent 1950 15.78359 1955 16.59796 1960 17.08031 1965 16.758 1970 15.99092 1975 14.97295 1980 14.00739 1985 13.55654 1990 12.84288 1995 12.43646 2000 11.92989 2005 11.34733 2010 11.25583 2015 11.45791 2020 11.93294 2025 12.39343 2030 12.65842 2035 12.93878 2040 13.44589 2045 14.45057 2050 15.92629 2055 17.39584 2060 18.74813 2065 19.91383 2070 20.92272 2075 21.92531 2080 22.86899 2085 23.63719 2090 24.18522 2095 24.56214 2100 24.82212