Year Percent 1950 13.8691 1955 13.94168 1960 13.51607 1965 13.24505 1970 13.42877 1975 13.75238 1980 14.49961 1985 15.46055 1990 16.94786 1995 18.91859 2000 22.68484 2005 25.79133 2010 28.93834 2015 30.42887 2020 30.58454 2025 29.48885 2030 27.72249 2035 26.85545 2040 26.71218 2045 26.89743 2050 27.29791 2055 26.85148 2060 25.65974 2065 24.67054 2070 23.91593 2075 23.43437 2080 23.42313 2085 23.5325 2090 23.4629 2095 23.24567 2100 23.04306