Year Percent 1950 17.39882 1955 17.19621 1960 16.63479 1965 16.1933 1970 15.83251 1975 15.41921 1980 14.92679 1985 14.3374 1990 13.59152 1995 13.11995 2000 12.77962 2005 12.42655 2010 12.30134 2015 12.08268 2020 12.19384 2025 12.55782 2030 13.10131 2035 14.0074 2040 15.57228 2045 17.4587 2050 19.19065 2055 20.48713 2060 21.09881 2065 21.64991 2070 22.42058 2075 23.30444 2080 24.16825 2085 24.68031 2090 24.89767 2095 25.01804 2100 25.19521