| Year | Value | | 2022 | -1.0557195773697 | | 2021 | 0.25104763171898 | | 2020 | 0.25659429857372 | | 2019 | 0.41055693540679 | | 2018 | 0.39829692290949 | | 2017 | 0.43286792819397 | | 2016 | 0.47603997197581 | | 2015 | 0.48927360473574 | | 2014 | 0.48414680741276 | | 2013 | 0.4799738630753 | | 2012 | 0.43782336005738 | | 2011 | 0.48814128531305 | | 2010 | 0.44853994413872 | | 2009 | 0.38960121211488 | | 2008 | 0.27165334328355 | | 2007 | 0.085365594625685 | | 2006 | 0.12710141483834 | | 2005 | 0.092016081522402 | | 2004 | 0.0729364240254 | | 2003 | 0.019215726671831 | | 2002 | 0.079958408417355 | | 2001 | 0.091146012983117 | | 2000 | 0.08609930801083 | | 1999 | 0.023471096427613 | | 1998 | 0.064024646129937 | | 1997 | 0.12706218011904 | | 1996 | 0.15109959390725 | | 1995 | 0.1209931412735 | | 1994 | 0.21693935432027 | | 1993 | 0.3098403340753 | | 1992 | 0.38850509623668 | | 1991 | 0.5560695004646 | | 1990 | 0.61682427218986 | | 1989 | 0.79797202190093 | | 1988 | 0.97040763331131 | | 1987 | 1.015934933893 | | 1986 | 1.0210344732706 | | 1985 | 1.0376889039611 | | 1984 | 1.0570497732091 | | 1983 | 1.0009181016681 | | 1982 | 0.9852075802248 | | 1981 | 1.0032809008468 | | 1980 | 1.0072657502258 | | 1979 | 1.0022247509182 | | 1978 | 1.0317599557132 | | 1977 | 1.0679675019616 | | 1976 | 1.080309772827 | | 1975 | 1.0424457559676 | | 1974 | 1.0433683166662 | | 1973 | 1.0434736766826 | | 1972 | 1.0564925428939 | | 1971 | 1.0093690080008 | | 1970 | 1.0310141484866 | | 1969 | 1.1259492626229 | | 1968 | 1.1980282026243 | | 1967 | 1.2367956611212 | | 1966 | 1.1804052205522 | | 1965 | 1.3998344254138 | | 1964 | 1.4904510454174 | | 1963 | 1.5060170940794 | | 1962 | 1.5120555011375 | | 1961 | 1.5353263480077 |
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