| Year | Value | | 2022 | 0.60507515301541 | | 2021 | -4.256648901921 | | 2020 | 0.43321022083776 | | 2019 | 0.55414673904289 | | 2018 | 0.89348692771106 | | 2017 | -1.2006101648092 | | 2016 | 0.69838345731273 | | 2015 | 0.82409916391354 | | 2014 | 0.40734318477763 | | 2013 | 0.27850906285013 | | 2012 | 0.30565594479591 | | 2011 | 0.34526422848582 | | 2010 | 0.22682127081842 | | 2009 | 0.10502751669287 | | 2008 | 0.011879457855928 | | 2007 | 0.021852660265571 | | 2006 | 0.023523123756575 | | 2005 | 0.12873278932275 | | 2004 | 0.027904278515666 | | 2003 | 0.028469923113185 | | 2002 | 0.05887129120477 | | 2001 | -3.8476707266781 | | 2000 | 0.98643485864557 | | 1999 | 0.43203116222509 | | 1998 | 0.061431194309139 | | 1997 | 0.4878355150747 | | 1996 | -1.3715400590127 | | 1995 | 0.6901195135419 | | 1994 | 1.1145443110605 | | 1993 | 0.5371470044604 | | 1992 | -2.4438551369122 | | 1991 | -1.8665735308856 | | 1990 | 0.21180508614532 | | 1989 | 0.2531488202949 | | 1988 | 0.32568913813482 | | 1987 | 0.38682281792242 | | 1986 | 0.42511559733407 | | 1985 | 0.4504947127651 | | 1984 | 0.47183056946942 | | 1983 | 0.51697787498341 | | 1982 | 0.49157857323862 | | 1981 | 0.25462242666664 | | 1980 | 0.10884698112901 | | 1979 | 0.29845716232663 | | 1978 | 0.47073294799172 | | 1977 | 0.519752409818 | | 1976 | 0.52723282655623 | | 1975 | 0.47590035192932 | | 1974 | 0.45752583962487 | | 1973 | 0.43935961537923 | | 1972 | 0.43434766888199 | | 1971 | 0.43021363174207 | | 1970 | 0.47166394677319 | | 1969 | 0.59065265963933 | | 1968 | 0.61912048108228 | | 1967 | 0.6470309936968 | | 1966 | 0.69318953527042 | | 1965 | 0.6573180592792 | | 1964 | 0.64164485945477 | | 1963 | 0.68776498081577 | | 1962 | 0.70349371745206 | | 1961 | 0.65269176909661 |
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