| Year | Value | | 2022 | 4.9947659638104 | | 2021 | 6.0418648905804 | | 2020 | 0.5741626794258 | | 2019 | 0.19896538002393 | | 2018 | 0.36744148893685 | | 2017 | 0.18405889884769 | | 2016 | 0.55652139715551 | | 2015 | 1.3933302878031 | | 2014 | 2.2359740790468 | | 2013 | 1.8794980074947 | | 2012 | 6.0890964159504 | | 2011 | 5.801455370853 | | 2010 | 2.8777472527476 | | 2009 | 6.8736154721255 | | 2008 | 12.662852826923 | | 2007 | -10.067492576898 | | 2006 | 53.230962911428 | | 2005 | 36.959480920187 | | 2004 | 26.961906819327 | | 2003 | 33.616210599238 | | 2002 | 19.316694601979 | | 2001 | 16.374081496326 | | 2000 | 4.9789621318374 | | 1999 | 12.577762339344 | | 1998 | 14.768773557553 | | 1997 | 23.063199678873 | | 1996 | -16.117325751057 | | 1995 | 387.31084776664 | | 1994 | 448.5 | | 1993 | 207.69230769231 | | 1992 | 83.615819209039 | | 1991 | 180.95238095238 | | 1978 | 4.6119428668202 | | 1977 | 9.1677625399551 | | 1976 | 12.823230182813 | | 1975 | 9.5171773440554 | | 1974 | 7.6999999997693 | | 1973 | 4.8909840899257 | | 1972 | 5.1859504132552 | | 1971 | 3.5958904107604 | | 1970 | 4.3555952647056 | | 1969 | 5.7392536613673 | | 1968 | 2.196475982868 | | 1967 | 3.2909498878167 | | 1966 | 1.9832189171216 | | 1965 | 0.45558086585781 | | 1964 | 0.090136519671748 | | 1963 | 3.9549574292974 | | 1962 | 1.2923621654152 | | 1961 | 0.91626043184669 | | 1960 | 3.478237904096 |
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