| Year | Value | | 2022 | 9.3938387745653 | | 2021 | 2.2424887957772 | | 2020 | 1.1400093939319 | | 2019 | 0.24660026814783 | | 2018 | 0.38132470279135 | | 2017 | 1.6911146182231 | | 2016 | 1.5031205586107 | | 2015 | 1.4767204891047 | | 2014 | -1.5092446057048 | | 2013 | 1.2071255566839 | | 2012 | 2.1305458027449 | | 2011 | 5.0461022632021 | | 2010 | 2.517851401717 | | 2009 | -1.6513973362078 | | 2008 | 10.460073135471 | | 2007 | 4.61743772242 | | 2006 | 1.9547371762892 | | 2005 | 3.3291992280286 | | 2004 | 0.88330269693094 | | 2003 | -3.5025855110342 | | 2002 | 3.3001217528375 | | 2001 | 3.3481226552711 | | 2000 | 8.6363209493028 | | 1999 | -2.0863051322353 | | 1998 | 8.013755189656 | | 1997 | 49.100923576953 | | 1996 | 50.734054961212 | | 1995 | 45.365308362186 | | 1994 | 15.176347431344 | | 1993 | 48.108166068707 | | 1992 | 69.583636399379 | | 1991 | 57.595284750566 | | 1990 | 33.001977831802 | | 1989 | 80.788140643623 | | 1988 | 60.281782633354 |
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