| Year | Value | | 2021 | 52.67573808 | | 2020 | 47.11190815 | | 2019 | 43.02661187 | | 2018 | 44.1 | | 2017 | 41.6 | | 2016 | 39.2 | | 2015 | 36.9 | | 2014 | 34.7 | | 2013 | 32.7 | | 2012 | 30.8 | | 2011 | 29 | | 2010 | 25 | | 2009 | 9 | | 2008 | 6.22 | | 2007 | 5.97 | | 2006 | 5.740586325 | | 2005 | 5.397636329 | | 2004 | 5.243628452 | | 2003 | 4.857672267 | | 2002 | 4.332275746 | | 2001 | 2.52400566 | | 2000 | 1.982253196 | | 1999 | 1.431608803 | | 1998 | 1.103405994 | | 1997 | 0.136912963 | | 1996 | 0.055946029 | | 1995 | 0.028585702 | | 1994 | 0.005844253 |
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