| Year | Value | | 2022 | -1.261613265181 | | 2021 | 0.57650768986937 | | 2020 | 2.7139764316341 | | 2019 | 0.010646545957411 | | 2018 | -4.0483910336329 | | 2017 | -2.4180176217623 | | 2016 | -1.9349710903462 | | 2015 | -1.7592082581518 | | 2014 | -1.6331283312239 | | 2013 | -1.1459309783814 | | 2012 | -1.2099879342229 | | 2011 | -1.1565402929399 | | 2010 | 0.50617005698218 | | 2009 | 0.54540189449208 | | 2008 | 0.58667739163101 | | 2007 | 0.58562075715953 | | 2006 | 0.42346720549535 | | 2005 | 0.14424236050061 | | 2004 | 0.020462635964688 | | 2003 | 0.062589906401526 | | 2002 | 0.1289373058489 | | 2001 | 0.21414595137601 | | 2000 | 0.27655868886741 | | 1999 | 0.50071452326945 | | 1998 | 0.57478868966152 | | 1997 | 0.92931200727283 | | 1996 | 1.1218626688925 | | 1995 | 0.9237498757298 | | 1994 | 0.92887757746017 | | 1993 | 0.84217625803236 | | 1992 | 0.6454500373572 | | 1991 | 0.70741556945338 | | 1990 | 0.89029575723368 | | 1989 | 0.909864623032 | | 1988 | 0.92681888952973 | | 1987 | 0.94276265728124 | | 1986 | 0.95937495491466 | | 1985 | 0.9763229613249 | | 1984 | 0.99325748426467 | | 1983 | 1.022534059296 | | 1982 | 1.0705922266223 | | 1981 | 1.133661990099 | | 1980 | 1.1895802843199 | | 1979 | 1.2280247929314 | | 1978 | 1.3100950616712 | | 1977 | 1.4622577155275 | | 1976 | 1.6514189645424 | | 1975 | 1.8439168451229 | | 1974 | 2.0802440043939 | | 1973 | 2.160531591777 | | 1972 | 1.9739518232018 | | 1971 | 1.6127527623529 | | 1970 | 1.2532211444907 | | 1969 | 0.82623425265018 | | 1968 | 0.61759084926086 | | 1967 | 0.78468619850657 | | 1966 | 1.1877905385616 | | 1965 | 1.5514486801041 | | 1964 | 1.9585506910608 | | 1963 | 2.1881647690517 | | 1962 | 2.0866547180718 | | 1961 | 1.7539095196189 |
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