| Year | Value | | 2014 | 3,507.4045206547 | | 2013 | 3,472.5413845548 | | 2012 | 3,587.9328659861 | | 2011 | 3,264.0533201535 | | 2010 | 3,229.9510620699 | | 2009 | 3,026.6114885167 | | 2008 | 3,213.1214400075 | | 2007 | 3,169.0772953995 | | 2006 | 2,966.6099730566 | | 2005 | 2,777.3819802492 | | 2004 | 2,607.4599601789 | | 2003 | 2,493.9301690811 | | 2002 | 2,307.186518066 | | 2001 | 2,213.3606027803 | | 2000 | 2,082.3213870879 | | 1999 | 2,072.8037274491 | | 1998 | 2,129.8587272548 | | 1997 | 2,056.4350221201 | | 1996 | 1,992.9009263306 | | 1995 | 1,997.1380926627 | | 1994 | 1,973.2285176349 | | 1993 | 2,048.1490584366 | | 1992 | 2,638.9089704545 | | 1991 | 3,285.3174454959 | | 1990 | 3,396.7281614899 |
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