Year Percent 1950 11.52472 1955 11.93772 1960 13.33815 1965 15.10248 1970 16.72109 1975 17.31987 1980 14.79103 1985 15.42672 1990 17.86461 1995 18.00925 2000 18.17321 2005 19.83076 2010 22.39781 2015 24.86723 2020 26.27788 2025 27.46063 2030 28.74744 2035 31.38428 2040 34.36784 2045 35.71014 2050 36.70821 2055 37.04142 2060 35.90591 2065 34.97288 2070 34.94936 2075 34.91074 2080 35.01145 2085 35.1453 2090 35.18063 2095 35.22515 2100 35.53126