| Year | Value | | 2022 | 19.398263408062 | | 2021 | 4.6531667384747 | | 2020 | 0.44453109767983 | | 2019 | 2.2772593124352 | | 2018 | 3.4363268842045 | | 2017 | 3.4172354948805 | | 2016 | 0.14868490762737 | | 2015 | 0.49232600654737 | | 2014 | 0.10617514652171 | | 2013 | 2.7805665895499 | | 2012 | 3.9333998729698 | | 2011 | 4.9819013145361 | | 2010 | 2.9720451201569 | | 2009 | 0.078408311280977 | | 2008 | 10.362358031368 | | 2007 | 6.6013260305564 | | 2006 | 4.4376204238921 | | 2005 | 4.0797142319985 | | 2004 | 3.0481110752342 | | 2003 | 1.3349911654996 | | 2002 | 3.5719127016403 | | 2001 | 5.7482798165137 | | 2000 | 4.0184895250876 | | 1999 | 3.2961108971891 | | 1998 | 8.208333333333 | | 1997 | 10.581878932215 | | 1996 | 23.050343349517 | | 1995 | 28.776613720851 | | 1994 | 47.654690618763 | | 1993 | 89.811949027727 |
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