| Year | Value | | 2021 | 21.0372074 | | 2020 | 18.93481469 | | 2019 | 17.07090172 | | 2018 | 15.34 | | 2017 | 13.78 | | 2016 | 12.38544676 | | 2015 | 11 | | 2014 | 10 | | 2013 | 9 | | 2012 | 8.1 | | 2011 | 8 | | 2010 | 8 | | 2009 | 7.5 | | 2008 | 7 | | 2007 | 6.8 | | 2006 | 6.5 | | 2005 | 6.332329098 | | 2004 | 6.164320985 | | 2003 | 5.041158126 | | 2002 | 2.577426737 | | 2001 | 1.318550779 | | 1999 | 0.055357238 | | 1998 | 0.043947719 | | 1997 | 0.027549238 | | 1996 | 0.00299173 | | 1995 | 0.000122702 |
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