| Year | Value | | 2022 | 0.10707201090113 | | 2021 | 0.075592142017157 | | 2020 | 0.14682134483006 | | 2019 | 0.1026468306272 | | 2018 | 0.050237582954293 | | 2017 | 0.0062779236834413 | | 2016 | 0.0041850635089555 | | 2015 | 0.0020925098610206 | | 2014 | 0.046046298272656 | | 2013 | 0.08377490175177 | | 2012 | 0.30637536031275 | | 2011 | 0.3748004050613 | | 2010 | 0.24712492379041 | | 2009 | 0.27530141696866 | | 2008 | 0.29945547008408 | | 2007 | 0.30035489993574 | | 2006 | 0.31837973880562 | | 2005 | 0.31080888854317 | | 2004 | 0.32039248574627 | | 2003 | 0.3603218742815 | | 2002 | 0.6027118516108 | | 2001 | 1.1482186797034 | | 2000 | 1.4088796051579 | | 1999 | 1.3362727610961 | | 1998 | 1.3062561996305 | | 1997 | 1.2887340765254 | | 1996 | 1.2773534099293 | | 1995 | 1.2986427495648 | | 1994 | 1.3277924918783 | | 1993 | 1.3285439556197 | | 1992 | 0.87915892506635 | | 1991 | 0.2315899431206 | | 1990 | 0.87225524850251 | | 1989 | 0.79939195995419 | | 1988 | 0.7137892323264 | | 1987 | 0.65145249910379 | | 1986 | 0.60690629327031 | | 1985 | 0.55842272792826 | | 1984 | 0.51777004351717 | | 1983 | 0.45436525694343 | | 1982 | 0.37085888074352 | | 1981 | 0.33468944664824 | | 1980 | 0.41910336309139 | | 1979 | 0.43115937814372 | | 1978 | 0.3169938796294 | | 1977 | 0.31370599213 | | 1976 | 0.33779189466256 | | 1975 | 0.3820617764933 | | 1974 | 0.42130121886505 | | 1973 | 0.39252007355084 | | 1972 | 0.37528555602028 | | 1971 | 0.85985052552319 | | 1970 | -2.5620755330745 | | 1969 | -3.4867812775661 | | 1968 | -3.0855386217353 | | 1967 | -2.8295468626151 | | 1966 | -2.5960814911865 | | 1965 | -2.354033333358 | | 1964 | -2.1107002103396 | | 1963 | -1.8453094314327 | | 1962 | -1.5100913016071 | | 1961 | 0.7315788073447 |
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