| Year | Value | | 2020 | 2.8071933883444 | | 2017 | 0.472 | | 2016 | 0.472 | | 2015 | 0.56564667 | | 2014 | 0.471265 | | 2013 | 4.99992 | | 2012 | 3.056 | | 2011 | 2.291 | | 2010 | 2.6402227027027 | | 2009 | 7.425 | | 2008 | 1.289 | | 2007 | 1.177 | | 2006 | 1.296 | | 2005 | 1.295 | | 2004 | 1.205 | | 2003 | 1.265 | | 2002 | 1.514 | | 2001 | 1.527 | | 2000 | 1.594 | | 1999 | 1.7999999523 | | 1998 | 2.5999999046 | | 1997 | 2.7999999523 | | 1996 | 1.7999999523 | | 1995 | 1.5 | | 1994 | 1.1000000238 | | 1993 | 0.6000000238 | | 1992 | 4.3000001907 |
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