Year Percent 1950 28.96179 1955 28.55008 1960 27.92445 1965 27.12401 1970 26.33418 1975 26.00137 1980 25.70569 1985 26.18601 1990 27.09374 1995 28.46961 2000 29.82698 2005 30.40449 2010 30.3463 2015 28.47967 2020 27.61076 2025 27.79046 2030 28.94753 2035 30.16873 2040 30.58467 2045 30.5776 2050 30.34877 2055 30.21692 2060 30.32929 2065 30.32481 2070 30.08805 2075 29.6917 2080 29.28283 2085 28.96148 2090 28.6687 2095 28.3397 2100 27.95584