| Year | Value | | 2021 | 0.41753870339316 | | 2020 | -4.5795047639756 | | 2019 | 10.51287893715 | | 2018 | 3.6201693473467 | | 2017 | 0.85992833070362 | | 2016 | 6.9593105184754 | | 2015 | 4.9545029174936 | | 2014 | 6.457922409865 | | 2013 | 1.2415866804903 | | 2012 | 4.0333613962493 | | 2011 | 7.5865120043131 | | 2010 | 9.3165607526976 | | 2009 | 5.580131241032 | | 2008 | 7.2226681107478 | | 2007 | 13.64311455294 | | 2006 | 4.081213214837 | | 2005 | 7.7868283112756 | | 2004 | 6.4972256659131 | | 2003 | 6.1109537256343 | | 2002 | 10.309563200537 | | 2001 | 10.630446458673 | | 2000 | 35.508083691127 | | 1999 | 4.1019241704225 | | 1998 | -2.3756585502762 | | 1997 | 12.959207049978 | | 1996 | 5.9613084679655 | | 1995 | 0.24149181727996 | | 1994 | 13.242843155581 | | 1993 | 1.9179390770822 | | 1992 | 0.49491046796515 | | 1991 | -5.8452662964272 |
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