| Year | Value | | 2014 | 15,297.810709531 | | 2013 | 14,694.56615873 | | 2012 | 15,837.212707123 | | 2011 | 16,023.474589075 | | 2010 | 17,033.617408156 | | 2009 | 16,669.70721325 | | 2008 | 17,063.822884799 | | 2007 | 17,074.568897254 | | 2006 | 17,842.870193014 | | 2005 | 17,342.286827028 | | 2004 | 17,050.533531524 | | 2003 | 16,856.482922247 | | 2002 | 15,806.666523393 | | 2001 | 15,326.80549126 | | 2000 | 14,867.427325739 | | 1999 | 14,968.890934241 | | 1998 | 14,666.31199905 | | 1997 | 13,502.374156102 | | 1996 | 13,311.078729867 | | 1995 | 12,755.992851714 | | 1994 | 12,766.999815978 | | 1993 | 11,542.985344497 | | 1992 | 9,793.7040650166 | | 1991 | 7,532.6614408361 | | 1990 | 10,286.947934789 | | 1989 | 8,868.2736255398 | | 1988 | 8,532.9706225903 | | 1987 | 8,173.8774709211 | | 1986 | 7,959.4815895387 | | 1985 | 7,508.8341560899 | | 1984 | 7,046.360887019 | | 1983 | 6,623.7410917335 | | 1982 | 6,511.5029695914 | | 1981 | 5,857.5001303221 | | 1980 | 5,556.7084150562 | | 1979 | 5,612.9652629179 | | 1978 | 4,833.4404254391 | | 1977 | 4,420.2128725771 | | 1976 | 4,078.5735003093 | | 1975 | 3,890.5180483906 | | 1974 | 3,638.3010521862 | | 1973 | 3,461.0062368177 | | 1972 | 3,303.840618964 | | 1971 | 2,809.9504619591 |
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