Year Percent 1950 27.48655 1955 27.21597 1960 26.8747 1965 26.41811 1970 26.09103 1975 25.8932 1980 25.88552 1985 26.29592 1990 27.06447 1995 27.89127 2000 28.17527 2005 28.44367 2010 27.37618 2015 28.08777 2020 29.26624 2025 30.59007 2030 31.58272 2035 31.83478 2040 31.67688 2045 31.40555 2050 31.24069 2055 31.18548 2060 31.1012 2065 30.89149 2070 30.55879 2075 30.19257 2080 29.88037 2085 29.64574 2090 29.42815 2095 29.1688 2100 28.83585