| Year | Value | | 2014 | -17.71675284392 | | 2013 | -10.239082113966 | | 2012 | 1.4127555391844 | | 2011 | 1.9924755643177 | | 2010 | 13.576434153183 | | 2009 | -21.586847065974 | | 2008 | 10.383633373626 | | 2007 | 14.840878932681 | | 2006 | 17.67069540531 | | 2005 | 24.909326265394 | | 2004 | 32.259839940996 | | 2003 | -5.7093329045441 | | 2002 | -10.023456237662 | | 2001 | 0.68461625790138 | | 2000 | 15.756625456626 | | 1999 | 0.18825873533086 | | 1998 | -4.7270635823583 | | 1997 | 6.2902338678184 | | 1996 | 0.81756744713859 | | 1995 | 7.3938864809999 | | 1994 | -5.3349490871619 | | 1993 | -6.3148492094253 | | 1992 | 6.599146516379 | | 1991 | 10.952026286819 | | 1990 | 12.337095639853 | | 1989 | -11.190267972522 | | 1988 | 4.5501483859247 | | 1987 | 5.0709746759149 | | 1986 | -4.8077555361069 | | 1985 | 4.6697466150717 | | 1984 | 31.367173064289 | | 1983 | -15.903103142943 | | 1982 | 2.2710573351984 | | 1981 | 10.564799709387 | | 1980 | 10.703614063324 | | 1979 | -15.623155524005 | | 1978 | -4.6522822020645 | | 1977 | 13.135438442599 | | 1976 | 11.363925531015 | | 1975 | 20.793434220574 | | 1974 | -10.173745466229 | | 1973 | 6.0468165589006 | | 1972 | 5.6725795599915 | | 1971 | -11.900692051939 |
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