Year Percent 1950 12.82315 1955 12.78146 1960 12.46373 1965 9.79434 1970 12.2712 1975 13.16011 1980 12.78613 1985 11.46197 1990 11.3401 1995 13.43498 2000 15.67544 2005 17.41236 2010 20.86639 2015 22.56927 2020 23.05369 2025 23.6085 2030 22.79321 2035 24.76405 2040 27.41377 2045 29.66782 2050 30.29509 2055 28.94854 2060 26.78963 2065 25.1841 2070 24.86704 2075 25.0083 2080 24.92674 2085 24.50824 2090 23.93249 2095 23.33979 2100 23.08609