| Year | Value | | 2021 | -8.9078174523893 | | 2020 | 2.5172816109935 | | 2019 | 2.911933745962 | | 2018 | 2.0703438196905 | | 2017 | 0.63177281104221 | | 2016 | 7.3988576694311 | | 2015 | 7.9252653328896 | | 2014 | 11.21632758895 | | 2013 | 1.2853013826456 | | 2012 | -3.0406224804767 | | 2011 | 5.9634366992746 | | 2010 | 8.2444566610872 | | 2009 | 8.1757772880734 | | 2008 | 6.9606809833334 | | 2007 | 1.5572174504726 | | 2006 | 4.9602208330255 | | 2005 | 5.6095401938944 | | 2004 | 1.6958066357011 | | 2003 | 15.504317761949 | | 2002 | -2.7335463854313 | | 2001 | 11.082611703153 | | 2000 | -2.9586535437981 | | 1999 | 3.9861319325817 | | 1998 | 12.609896860133 | | 1997 | 4.0241456279857 | | 1996 | 7.5403437482926 | | 1995 | 5.4961487345504 | | 1994 | -6.5035917589688 | | 1993 | 5.1496414849223 | | 1992 | -5.2722957078217 | | 1991 | 9.4074407153122 | | 1990 | -2.5246878686267 | | 1989 | 6.405360291062 | | 1988 | 1.9204002385996 | | 1987 | 4.3321282329554 | | 1986 | 4.7468665609539 |
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