| Year | Value | | 2013 | -4.2948733153674 | | 2012 | 6.314744503152 | | 2011 | 1.8426630075621 | | 2010 | 3.3547577032892 | | 2009 | 4.3623482932572 | | 2008 | 1.7007817628453 | | 2007 | 4.4661671009813 | | 2006 | 3.3743636012121 | | 2005 | 3.0133239505812 | | 2004 | 4.4749928907811 | | 2003 | 3.799081366719 | | 2002 | 3.5330421430808 | | 2001 | 5.5545939481681 |
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