Year Percent 1950 12.66679 1955 13.37481 1960 15.0887 1965 16.97671 1970 18.72556 1975 19.41478 1980 16.81263 1985 17.54512 1990 20.88731 1995 21.02333 2000 21.1407 2005 22.72827 2010 25.32581 2015 27.77874 2020 29.12292 2025 30.2084 2030 31.36024 2035 33.80425 2040 36.5594 2045 37.67228 2050 38.51185 2055 38.79364 2060 37.65702 2065 36.72358 2070 36.65134 2075 36.52807 2080 36.53451 2085 36.59094 2090 36.5688 2095 36.59673 2100 36.91522