| Year | Value | | 2021 | 17.8688792 | | 2020 | 11.66019198 | | 2019 | 8.364171285 | | 2018 | 8 | | 2017 | 7.4 | | 2016 | 5.8 | | 2015 | 3.5 | | 2014 | 2.9 | | 2013 | 2.5 | | 2012 | 2.1 | | 2011 | 1.9 | | 2010 | 1.7 | | 2009 | 1.5 | | 2008 | 1.19 | | 2007 | 0.847224521 | | 2006 | 0.581045764 | | 2005 | 0.3992577 | | 2004 | 0.360920107 | | 2003 | 0.320308555 | | 2002 | 0.166069665 | | 2001 | 0.045934134 | | 2000 | 0.035707076 | | 1999 | 0.012321728 | | 1998 | 0.004268504 | | 1997 | 0.000658168 |
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