| Year | Value | | 2022 | 1.0936680800501 | | 2021 | 0.21280542953683 | | 2020 | 0.026766758279567 | | 2019 | 0.26470435494479 | | 2018 | 0.95419045920997 | | 2017 | -1.398322200921 | | 2016 | -1.2706945329886 | | 2015 | 0.94075379664621 | | 2014 | 0.85982734307025 | | 2013 | -1.012007368181 | | 2012 | -1.341201988216 | | 2011 | -2.2584638988283 | | 2010 | -2.0969434198548 | | 2009 | -1.1103457543724 | | 2008 | -1.0284831754654 | | 2007 | -1.187947957259 | | 2006 | -1.5963783183009 | | 2005 | -1.6284011259343 | | 2004 | -1.1229912748324 | | 2003 | 0.81227809740669 | | 2002 | 0.80276571074851 | | 2001 | 0.82400872304418 | | 2000 | 0.70338544048898 | | 1999 | 0.70948923407161 | | 1998 | 0.7244362066002 | | 1997 | 0.73783035806663 | | 1996 | 0.76034340817449 | | 1995 | 0.76972801777074 | | 1994 | 0.69400396291902 | | 1993 | 0.47410754270016 | | 1992 | 0.10858632490425 | | 1991 | 0.17011686935243 | | 1990 | 0.36799903032336 | | 1989 | 0.79588348340029 | | 1988 | 1.0639568661969 | | 1987 | 1.0410528305869 | | 1986 | 0.96501647261471 | | 1985 | 0.85959115710707 | | 1984 | 0.8290190187848 | | 1983 | 0.80701973535907 | | 1982 | 0.70338626338287 | | 1981 | 0.57682223237947 | | 1980 | 0.45103294117972 | | 1979 | 0.54086120543731 | | 1978 | 0.72694115549103 | | 1977 | 0.78914783310129 | | 1976 | 0.81480730167874 | | 1975 | 0.84428471449163 | | 1974 | 0.90379564920391 | | 1973 | 0.95434956902678 | | 1972 | 1.0819070961443 | | 1971 | 1.2455828554027 | | 1970 | 1.0362810259716 | | 1969 | 0.92047895295209 | | 1968 | 1.12523132286 | | 1967 | 1.201180912123 | | 1966 | 1.2241979125452 | | 1965 | 1.2274455105482 | | 1964 | 1.2426991594818 | | 1963 | 1.2356334431234 | | 1962 | 1.3997309541126 | | 1961 | 1.6065749594616 |
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