Year Percent 1950 29.28126 1955 29.45003 1960 29.41053 1965 29.0815 1970 27.84518 1975 27.05652 1980 26.44899 1985 26.06224 1990 26.56049 1995 27.35056 2000 28.02658 2005 28.54098 2010 28.70368 2015 28.60816 2020 28.99468 2025 29.69306 2030 30.41748 2035 31.00711 2040 31.17733 2045 31.06932 2050 30.9661 2055 30.91195 2060 30.78758 2065 30.53352 2070 30.17087 2075 29.7555 2080 29.31429 2085 28.8856 2090 28.4456 2095 27.97788 2100 27.48065