| Year | Value | | 2021 | 1.5620828529433 | | 2020 | -6.147753736949 | | 2019 | 1.5986160222983 | | 2018 | 0.63923353116732 | | 2017 | 0.29278727367621 | | 2016 | 13.135634660677 | | 2015 | 0.75504877991894 | | 2014 | 0.96476528219156 | | 2013 | 6.7882706696595 | | 2012 | -2.5464481736966 | | 2011 | 4.5872396162396 | | 2010 | 8.4346626495462 | | 2009 | 3.276349800433 | | 2008 | 6.2101586218507 | | 2007 | 6.6716230529132 | | 2006 | 3.454934567567 | | 2005 | 7.037691683328 | | 2004 | 4.7755405986431 | | 2003 | -4.3082543552127 | | 2002 | -6.9778859803529 | | 2001 | -3.5363091435135 | | 2000 | -3.7002825515135 | | 1999 | -2.6951141096062 | | 1998 | 5.4493590353238 | | 1997 | 3.5957113311457 | | 1996 | 6.4405227199549 | | 1995 | -1.561442150838 | | 1994 | 9.0286139413891 | | 1993 | 4.6663141384621 | | 1992 | 11.723241610574 | | 1991 | 7.3445237271989 | | 1990 | -3.8250301467873 | | 1989 | 1.5793255010932 | | 1988 | 1.7202851633236 | | 1987 | 12.875605580524 | | 1986 | 16.667205396692 | | 1985 | 1.2534707840354 | | 1984 | -2.1683599716443 | | 1983 | -19.826842791364 | | 1982 | -11.551469575699 | | 1981 | 6.1608093248689 | | 1980 | 2.4532966287286 | | 1979 | 8.7426451346249 | | 1978 | 7.0608006873394 | | 1977 | 0.41865447584139 | | 1976 | 5.9431082330809 | | 1975 | 3.8136423543454 | | 1974 | 4.2801787399537 | | 1973 | -4.9506076989041 | | 1972 | -3.4940284419205 |
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