Year Percent 1950 20.90265 1955 21.45184 1960 21.03543 1965 21.39107 1970 22.15663 1975 22.83743 1980 22.86616 1985 22.64653 1990 22.58715 1995 22.90701 2000 25.07368 2005 27.17684 2010 29.04391 2015 31.71158 2020 33.21668 2025 32.24637 2030 29.71613 2035 26.30531 2040 22.97284 2045 22.02584 2050 22.8674 2055 23.6066 2060 24.19491 2065 23.86131 2070 22.77767 2075 22.27445 2080 22.24228 2085 22.58528 2090 22.92763 2095 22.98017 2100 22.70896