| Year | Value | | 2020 | 13.8152 | | 2017 | 26.7184 | | 2016 | 24.5792 | | 2015 | 24.0854 | | 2014 | 22.55 | | 2013 | 20 | | 2012 | 17.4465 | | 2011 | 14.905 | | 2010 | 12.35 | | 2009 | 9.96 | | 2008 | 6.89 | | 2007 | 5.01 | | 2006 | 1.24782 | | 2005 | 1.0486 | | 2004 | 0.881223 | | 2003 | 0.604734 | | 2002 | 0.518796 | | 2001 | 0.0908025 | | 2000 | 0.0825004 | | 1999 | 0.0566 | | 1998 | 0.0233 | | 1997 | 0.015 | | 1996 | 0.000621 |
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