Year Percent 1950 23.49555 1955 23.612 1960 21.13504 1965 20.50529 1970 21.39908 1975 23.90292 1980 26.54452 1985 26.13422 1990 26.30437 1995 27.46959 2000 27.44487 2005 29.68975 2010 29.16668 2015 28.43047 2020 28.29405 2025 28.43865 2030 28.95289 2035 28.26026 2040 27.57505 2045 26.06886 2050 25.43283 2055 25.40053 2060 24.83095 2065 24.80302 2070 24.01098 2075 23.35356 2080 23.10809 2085 23.17963 2090 23.29913 2095 23.30684 2100 23.13057