| Year | Value | | 2014 | 1,976.8644915275 | | 2013 | 1,928.7340356416 | | 2012 | 1,872.4130796477 | | 2011 | 1,774.6816634892 | | 2010 | 1,685.8472663785 | | 2009 | 1,618.5967933027 | | 2008 | 1,626.9912962334 | | 2007 | 1,730.7988668593 | | 2006 | 1,602.848980633 | | 2005 | 1,488.5572087058 | | 2004 | 1,409.7715237243 | | 2003 | 1,292.1103128236 | | 2002 | 1,208.0371345011 | | 2001 | 1,235.8236946852 | | 2000 | 1,257.0525762319 | | 1999 | 1,259.8135388627 | | 1998 | 1,255.3424572989 | | 1997 | 1,445.244844896 | | 1996 | 1,171.60336573 | | 1995 | 1,016.918955261 | | 1994 | 1,017.573219773 | | 1993 | 1,162.4513463929 | | 1992 | 1,890.3052268045 | | 1991 | 2,606.1253897924 | | 1990 | 2,708.5320869531 |
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