Year Percent 1950 14.22394 1955 15.71142 1960 16.20047 1965 15.91608 1970 15.71466 1975 16.98343 1980 18.47367 1985 20.0421 1990 23.32264 1995 25.36602 2000 27.84832 2005 31.24261 2010 32.93609 2015 32.49973 2020 30.49406 2025 26.7743 2030 23.62311 2035 23.0546 2040 23.54464 2045 24.79361 2050 26.50923 2055 25.54672 2060 24.23643 2065 23.44749 2070 23.21487 2075 23.91443 2080 24.24724 2085 23.99196 2090 23.32774 2095 22.78624 2100 22.65492