Year Percent 1950 27.48001 1955 27.43657 1960 27.21745 1965 26.98469 1970 26.87128 1975 26.57569 1980 26.48498 1985 26.58664 1990 26.78158 1995 27.27298 2000 27.87877 2005 28.10012 2010 27.84739 2015 27.55268 2020 27.63797 2025 28.10049 2030 28.96048 2035 29.83921 2040 30.37367 2045 30.66293 2050 30.74295 2055 30.74098 2060 30.77396 2065 30.74176 2070 30.57217 2075 30.30077 2080 29.98711 2085 29.64992 2090 29.31527 2095 28.95829 2100 28.57009