| Year | Value | | 2021 | 65.237085529214 | | 2020 | 61.166059340428 | | 2019 | 55.030102042041 | | 2017 | 40.544131803743 | | 2016 | 31.942898513633 | | 2015 | 27.887123579021 | | 2014 | 24.638298602251 | | 2013 | 21.964824499138 | | 2012 | 20.688019320978 | | 2011 | 17.642953985699 | | 2010 | 12.984587252081 | | 2009 | 10.904280965924 | | 2008 | 8.7319996591097 | | 2007 | 7.4472191312749 | | 2006 | 6.5522733621883 | | 2005 | 5.6305624980916 | | 2004 | 5.1994282396298 | | 2003 | 4.5645227866303 | | 2002 | 4.0018168689639 | | 2001 | 1.8804677929667 | | 2000 | 1.4567183606461 | | 1999 | 0.86930609307397 | | 1998 | 0.61147510539071 | | 1997 | 0.28594806531415 | | 1996 | 0.13218130634543 | | 1995 | 0.015256387704441 | | 1994 | 0.0033434973991802 | | 1993 | 0.0028538027833535 |
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