| Year | Value | | 2021 | 6.6616556918138 | | 2020 | -1.7903892869975 | | 2019 | 0.65522523860848 | | 2018 | -1.2203054278534 | | 2017 | 0.035629780521717 | | 2016 | 8.3590042730789 | | 2015 | -5.1013854220866 | | 2014 | 0.010144907626895 | | 2013 | 1.0396865708333 | | 2012 | 0.082182936533854 | | 2011 | 3.5970646431985 | | 2010 | 9.6168888781872 | | 2009 | 1.5478112149261 | | 2008 | 3.5776149160937 | | 2007 | 10.798569890753 | | 2006 | 6.5665623828989 | | 2005 | 6.8972904179789 | | 2004 | 3.9129494151195 | | 2003 | 4.3925705297032 | | 2002 | 9.0925446811134 | | 2001 | 9.556468396535 | | 2000 | 4.947722936558 | | 1999 | 5.2793277743607 | | 1998 | 1.6687417976228 | | 1997 | 4.3976845495258 | | 1996 | 7.4899054079262 | | 1995 | 0.98336725298753 | | 1994 | 2.760790831518 |
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