| Year | Value | | 2017 | 41.24872764 | | 2016 | 39.95 | | 2015 | 38.65127243 | | 2014 | 35.95444145 | | 2013 | 32.75396061 | | 2012 | 30 | | 2011 | 25 | | 2010 | 16 | | 2009 | 10 | | 2008 | 8.110769944 | | 2007 | 7.179865329 | | 2006 | 5.853944095 | | 2005 | 4.907782762 | | 2004 | 3.952373895 | | 2003 | 2.985817368 | | 2002 | 2.907297316 | | 2001 | 2.825371839 | | 2000 | 2.434398044 | | 1999 | 1.01796712 | | 1998 | 0.765134358 | | 1997 | 0.510866122 | | 1996 | 0.163793456 | | 1995 | 0.12323112 |
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