| Year | Value | | 2022 | 8.6409110897385 | | 2021 | 7.1848362944337 | | 2020 | 1.2114357783847 | | 2019 | 1.443446607707 | | 2018 | 2.5202338200164 | | 2017 | 0.96955326881614 | | 2016 | -1.403607559009 | | 2015 | 3.7316911926169 | | 2014 | 2.9813086893367 | | 2013 | 5.7896677854465 | | 2012 | 2.5580200775791 | | 2011 | 7.6500080785929 | | 2010 | 8.1763613847395 | | 2009 | 3.406766826838 | | 2008 | 8.9499533535339 | | 2007 | 4.4073608964452 | | 2006 | 2.89235662459 | | 2005 | 0.6389280024101 | | 2004 | 6.9612613587579 | | 2003 | 4.7215533660534 | | 2002 | 1.0600492934167 | | 2001 | 3.1459046468502 | | 2000 | 0.79088376893476 | | 1999 | 0.64824576047038 | | 1998 | 8.6724863238516 | | 1997 | 13.960764121791 | | 1996 | 18.681185640036 | | 1995 | 175.95132553458 | | 1994 | 3,373.7594433629 |
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