| Year | Value | | 2021 | 0.14853 | | 2020 | 0.17935 | | 2019 | 0.4406 | | 2018 | 0.52979 | | 2017 | 0.58275 | | 2016 | 0.65658 | | 2015 | 0.77532 | | 2014 | 0.97639 | | 2013 | 1.47223 | | 2012 | 1.738189 | | 2011 | 1.67474 | | 2010 | 1.516001 | | 2009 | 1.921 | | 2008 | 2.326 | | 2007 | 2.218 | | 2006 | 3.336 | | 2005 | 3.999 | | 2004 | 3.582 | | 2003 | 3.906 | | 2002 | 3.953 | | 2001 | 3.997 | | 2000 | 3.775 | | 1999 | 3.219 | | 1998 | 3.374 | | 1997 | 2 | | 1996 | 2.2999999523 | | 1995 | 2.4000000954 | | 1994 | 2.2999999523 | | 1993 | 1.7999999523 | | 1992 | 1.1000000238 |
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