Year Percent 1950 28.5214 1955 27.59799 1960 27.41778 1965 26.92053 1970 26.93703 1975 27.29912 1980 26.75454 1985 27.27333 1990 27.62547 1995 27.59646 2000 26.60025 2005 25.74624 2010 25.7635 2015 26.58443 2020 27.44034 2025 28.06768 2030 28.62651 2035 29.11264 2040 29.63477 2045 30.23788 2050 30.71243 2055 31.07472 2060 31.19119 2065 31.19886 2070 31.14256 2075 31.01071 2080 30.80157 2085 30.50036 2090 30.12486 2095 29.71888 2100 29.30349