Year Percent 1950 29.15696 1955 28.6147 1960 27.89295 1965 27.03009 1970 26.21224 1975 25.94498 1980 25.69503 1985 26.20797 1990 27.15655 1995 28.54817 2000 29.93613 2005 30.52602 2010 30.42187 2015 28.49847 2020 27.5986 2025 27.75553 2030 28.91084 2035 30.15229 2040 30.59748 2045 30.63444 2050 30.45536 2055 30.37227 2060 30.52856 2065 30.5606 2070 30.35614 2075 29.98903 2080 29.60877 2085 29.31608 2090 29.04767 2095 28.73638 2100 28.36424