| Year | Value | | 2022 | 2.3331433762457 | | 2021 | 0.54314968873701 | | 2020 | -1.3697742556981 | | 2019 | 0.22002973106538 | | 2018 | 0.13337338611759 | | 2017 | 2.8174733823451 | | 2016 | 0.50250941361161 | | 2015 | 0.95320665877761 | | 2014 | 2.1200017571813 | | 2013 | 3.8056300091943 | | 2012 | 10.884695658563 | | 2011 | 11.273414605594 | | 2010 | 6.1498853675017 | | 2009 | 4.530176591328 | | 2008 | 12.041458350511 | | 2007 | 6.7947735393017 | | 2006 | 2.738421316021 | | 2005 | 1.30027500931 | | 2004 | -1.6854121245947 | | 2003 | -1.2606511345035 | | 2002 | 4.1786723990479 | | 2001 | 0.67257737006247 | | 2000 | -1.1747568117595 | | 1999 | 2.9537083606913 | | 1998 | -1.4042523381679 | | 1997 | 7.5728346707259 | | 1996 | 6.2412459147603 | | 1995 | 5.488861331715 | | 1994 | 3.3861009829149 | | 1993 | 20.127359314925 | | 1992 | 16.855997753555 | | 1991 | 14.713677028273 | | 1990 | 3.6499119771748 | | 1989 | 7.1658588947078 | | 1988 | 6.4563602680194 | | 1987 | 9.7040723294332 | | 1986 | 9.7221932767856 |
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