| Year | Value | | 2021 | 2.2573 | | 2020 | 1.882857 | | 2019 | 2.8839 | | 2018 | 1.9004 | | 2017 | 1.9151 | | 2016 | 1.266 | | 2015 | 1.807 | | 2014 | 1.821996 | | 2013 | 1.695996 | | 2012 | 1.755 | | 2011 | 1.549 | | 2010 | 1.539 | | 2009 | 1.022 | | 2008 | 1.225 | | 2007 | 1.239 | | 2006 | 1.215 | | 2005 | 1.157 | | 2004 | 1.152 | | 2003 | 1.093 | | 2002 | 1.272 | | 2001 | 1.491 | | 2000 | 1.614 | | 1999 | 1.7999999523 | | 1998 | 3.5 | | 1997 | 2.5999999046 | | 1996 | 5.1999998093 | | 1995 | 2.4000000954 | | 1994 | 2.4000000954 | | 1993 | 2.4000000954 |
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