Year Percent 1950 18.44787 1955 18.22177 1960 19.08118 1965 17.94447 1970 16.31166 1975 14.9831 1980 15.56063 1985 16.21582 1990 15.19889 1995 17.74038 2000 18.24907 2005 18.81009 2010 19.79119 2015 21.10288 2020 21.79151 2025 21.86333 2030 20.74909 2035 20.06701 2040 20.06156 2045 20.75211 2050 21.99827 2055 22.66955 2060 22.80048 2065 22.68272 2070 22.53101 2075 22.58895 2080 22.79231 2085 22.93896 2090 22.9133 2095 22.74968 2100 22.54863