| Year | Value | | 2021 | -3.5387351159857 | | 2020 | 0.59424705487205 | | 2019 | 2.9334799718132 | | 2018 | -2.2642049046247 | | 2017 | -1.0622813927748 | | 2016 | 1.5033715352847 | | 2015 | 0.10289645243224 | | 2014 | 15.122538116886 | | 2013 | -12.880735018176 | | 2012 | 5.2286525220328 | | 2011 | 14.556170021206 | | 2010 | 21.459450590238 | | 2009 | 9.1820179484336 | | 2008 | 11.521353000103 | | 2007 | 11.659850773199 | | 2006 | -7.5855322340248 | | 2005 | 7.0528728428515 | | 2004 | 4.9860820367594 | | 2003 | 3.9128672044271 | | 2002 | 2.697625102613 | | 2001 | 0.11407594030589 | | 2000 | -9.4921936241598 | | 1999 | 0.72227452283276 | | 1998 | 2.4952690667403 | | 1997 | -3.3849649942516 | | 1996 | 1.9702763257172 | | 1995 | -3.3223971720641 | | 1994 | 5.1940850412976 | | 1993 | 0.049181562209672 | | 1992 | -2.853522667025 | | 1991 | 6.673974410409 | | 1990 | 4.0091466740437 | | 1989 | 10.159043255388 | | 1988 | 15.645245212309 | | 1987 | 15.555330909053 | | 1986 | 7.7810824421677 | | 1985 | 0.70238064496384 | | 1984 | 11.21596070551 | | 1983 | 3.8039878767549 | | 1982 | 5.2494597928246 | | 1981 | 3.7612128760867 | | 1980 | 2.9194096473064 | | 1979 | 16.813795973543 | | 1978 | 19.034322522043 | | 1977 | 10.976485077137 |
|