Year Percent 1950 18.93479 1955 18.0412 1960 17.94631 1965 17.0197 1970 16.57736 1975 16.49042 1980 16.80056 1985 17.00872 1990 17.44376 1995 19.77953 2000 21.74419 2005 25.06657 2010 28.7176 2015 30.09553 2020 30.20821 2025 29.66062 2030 30.00444 2035 29.09373 2040 28.43621 2045 27.40003 2050 24.85199 2055 24.4766 2060 25.23306 2065 25.52832 2070 25.04946 2075 24.01798 2080 23.29081 2085 23.12929 2090 23.23734 2095 23.27815 2100 23.08403