| Year | Value | | 2022 | 1.3365515114829 | | 2021 | 0.10599695631013 | | 2020 | 0.19755918517764 | | 2019 | 0.37155438903748 | | 2018 | 0.34803913798054 | | 2017 | 0.12107063146669 | | 2016 | 0.029112225554008 | | 2015 | 0.065552529541794 | | 2014 | 0.26225617509785 | | 2013 | 0.35589180262553 | | 2012 | 0.35794441144381 | | 2011 | 0.30358282364398 | | 2010 | 0.22805796852935 | | 2009 | 0.19276807742023 | | 2008 | 0.26813371954121 | | 2007 | 0.45618853509003 | | 2006 | 0.58965555984022 | | 2005 | 0.57225552465966 | | 2004 | 0.59782051039559 | | 2003 | 0.6276224480592 | | 2002 | 0.63343379642381 | | 2001 | 0.63696312445507 | | 2000 | 0.48370716172993 | | 1999 | 0.29448227591517 | | 1998 | 0.96055900458877 | | 1997 | -1.1409192402327 | | 1996 | -1.4753646375272 | | 1995 | -1.7853995357616 | | 1994 | -2.1385886350497 | | 1993 | -2.5743199780365 | | 1992 | -1.8241815553212 | | 1991 | 0.50215918519573 | | 1990 | 0.066490190684368 | | 1989 | 0.39814354752779 | | 1988 | 0.62162203507734 | | 1987 | 0.77810230921214 | | 1986 | 0.74350996200897 | | 1985 | 0.66706335629474 | | 1984 | 0.65218728331518 | | 1983 | 0.6870964018843 | | 1982 | 0.71987665537514 | | 1981 | 0.70471827646313 | | 1980 | 0.60335223799787 | | 1979 | 0.5562549151493 | | 1978 | 0.68561314665028 | | 1977 | 0.73604373010673 | | 1976 | 0.71274310695818 | | 1975 | 0.78545917618713 | | 1974 | 0.86526608136735 | | 1973 | 0.96003230139223 | | 1972 | 1.1239079653178 | | 1971 | 1.233395893442 | | 1970 | 1.0961454508679 | | 1969 | 1.0487818174434 | | 1968 | 0.92583750654613 | | 1967 | 0.78773618664579 | | 1966 | 1.0780067078473 | | 1965 | 1.3594583722588 | | 1964 | 1.4376753720288 | | 1963 | 1.3784771643384 | | 1962 | 1.3415695595657 | | 1961 | 1.1113897703949 |
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