| Year | Value | | 2021 | -1.1384645382602 | | 2020 | -5.1033358093774 | | 2019 | 1.5734873141458 | | 2018 | 9.1028373684049 | | 2017 | 2.7217882844177 | | 2016 | 7.766036008126 | | 2015 | 4.7188559058512 | | 2014 | 2.1668941378017 | | 2013 | 4.3493479984133 | | 2012 | 1.3001553635963 | | 2011 | 4.0983554646918 | | 2010 | 4.1085673669398 | | 2009 | -11.526963642929 | | 2008 | 8.6059229026115 | | 2007 | 3.8967489574729 | | 2006 | 5.463588516552 | | 2005 | 0.92733417733221 | | 2004 | 2.0509724646191 | | 2003 | 15.454885616034 | | 2002 | -14.524063287632 | | 2001 | 11.524948001173 | | 2000 | 5.677687695151 | | 1999 | 6.1933480278409 | | 1998 | 6.814974334536 | | 1997 | 3.4664390606696 | | 1996 | 5.9860471335106 | | 1995 | -2.2343272482037 | | 1994 | -4.0123562573614 | | 1993 | 3.6584467298525 | | 1992 | 1.6713476553105 | | 1991 | -11.456014376625 | | 1990 | 8.1396703910109 | | 1989 | -3.1981620257894 | | 1988 | 1.3053514610164 | | 1987 | -4.0990165704324 | | 1986 | 0.93594479434311 | | 1985 | 3.7409027235762 | | 1984 | 0.53698991959369 | | 1983 | 0.37800775119111 | | 1982 | -3.1859365673481 | | 1981 | -12.604646438416 |
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