| Year | Value | | 2022 | 5.5831673518325 | | 2021 | 4.2593641754287 | | 2020 | 1.7101565952315 | | 2019 | 2.6853735526679 | | 2018 | 1.6121568699155 | | 2017 | 4.1807233187127 | | 2016 | 4.9454327610652 | | 2015 | 1.4029701713682 | | 2014 | 14.898684179755 | | 2013 | 6.988793419702 | | 2012 | 5.4782959434612 | | 2011 | 1.1944757244985 | | 2010 | 1.491023700478 | | 2009 | 3.5212622723864 | | 2008 | 9.2589509941708 | | 2007 | 0.95991761945711 | | 2006 | 6.6952646577335 | | 2005 | 2.8835207335902 | | 2004 | -2.066406011363 | | 2003 | 4.13470905151 | | 2002 | 2.3318170351623 | | 2001 | 3.8348606023736 | | 2000 | 3.2034009156311 | | 1999 | -1.4142022008255 | | 1998 | -1.8852009615791 | | 1997 | 1.6113134776091 | | 1996 | 3.724941103258 | | 1995 | 19.18940397351 | | 1994 | 24.571013727561 | | 1993 | -2.9153584929834 | | 1992 | -1.0336081166778 | | 1991 | -2.7623628067576 | | 1990 | 0.01233045622721 | | 1989 | 0.68905580731274 | | 1988 | -3.9644688207937 | | 1987 | -6.9868027059997 | | 1986 | 2.2451525116227 | | 1985 | 10.423840230389 | | 1984 | 2.5422096681005 | | 1983 | 14.612611286881 | | 1982 | 13.296098699566 | | 1981 | 0.033333333333409 |
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