| Year | Value | | 2014 | 1,674.9881074507 | | 2013 | 1,714.6667513416 | | 2012 | 1,681.6841755595 | | 2011 | 1,629.1960944315 | | 2010 | 1,601.0319772912 | | 2009 | 1,593.3892961958 | | 2008 | 1,642.8327557992 | | 2007 | 1,602.2932231398 | | 2006 | 1,594.2147171137 | | 2005 | 1,502.3957327682 | | 2004 | 1,429.8192333116 | | 2003 | 1,147.5260059778 | | 2002 | 1,105.0952462901 | | 2001 | 1,070.888740693 | | 2000 | 1,037.8524809237 | | 1999 | 1,147.1778581177 | | 1998 | 1,083.554681492 | | 1997 | 993.36066551621 | | 1996 | 1,042.988583487 | | 1995 | 966.7553274323 | | 1994 | 975.32867613891 | | 1993 | 1,108.7311585247 | | 1992 | 1,043.3150188789 | | 1991 | 1,087.1584616461 |
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