| Year | Value | | 2021 | 1.347896 | | 2020 | 0.11692 | | 2019 | 0.3265 | | 2013 | 0.999996 | | 2012 | 3.0115 | | 2011 | 4.4857 | | 2010 | 5.9795 | | 2009 | 5.698 | | 2008 | 7.174 | | 2007 | 6.148 | | 2006 | 7.388 | | 2005 | 7.036 | | 2004 | 6.966 | | 2003 | 5.025 | | 2002 | 5.358 | | 2001 | 8.262 | | 2000 | 8.786 | | 1999 | 11.3000001907 | | 1998 | 10.3999996185 | | 1997 | 10.6999998093 | | 1996 | 11.8000001907 |
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