| Year | Value | | 2014 | 6,600.8982801222 | | 2013 | 6,710.0936782679 | | 2012 | 7,184.5016117818 | | 2011 | 6,930.0007726184 | | 2010 | 6,953.2766671913 | | 2009 | 6,607.8871433152 | | 2008 | 7,134.0028458844 | | 2007 | 7,003.2450801521 | | 2006 | 6,711.229567461 | | 2005 | 6,572.1995353602 | | 2004 | 6,525.9215743868 | | 2003 | 6,597.3063067103 | | 2002 | 6,502.7397260274 | | 2001 | 6,400.217425066 | | 2000 | 6,323.1038320878 | | 1999 | 5,974.3673469388 | | 1998 | 5,819.4607268464 | | 1997 | 5,488.5195339273 | | 1996 | 5,340.3021784961 | | 1995 | 5,127.8629395852 | | 1994 | 4,934.2470827931 | | 1993 | 4,618.893746436 | | 1992 | 4,568.4169431973 | | 1991 | 3,981.2083249141 | | 1990 | 4,176.1802575107 | | 1989 | 4,228.4196547145 | | 1988 | 4,026.1143628996 | | 1987 | 3,756.4660105287 | | 1986 | 3,407.0714119563 | | 1985 | 3,485.2350578786 | | 1984 | 3,359.4614089925 | | 1983 | 3,313.2764920828 | | 1982 | 3,173.9022575043 | | 1981 | 3,067.4924165824 | | 1980 | 3,022.1763795771 | | 1979 | 3,049.3924986793 | | 1978 | 3,011.9241192412 | | 1977 | 2,831.9955715472 | | 1976 | 2,718.0866119445 | | 1975 | 2,624.8914616498 | | 1974 | 2,518.2114302636 | | 1973 | 2,497.5594874924 | | 1972 | 2,497.1410419314 | | 1971 | 2,288.6933854676 |
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