| Year | Value | | 2021 | 79 | | 2020 | 78.67115844 | | 2019 | 78.96497802 | | 2017 | 70.6 | | 2016 | 67.8 | | 2015 | 65.1 | | 2014 | 62.4 | | 2013 | 59.9 | | 2012 | 57.5 | | 2011 | 55.2 | | 2010 | 48.5 | | 2009 | 44.3 | | 2008 | 34.8 | | 2007 | 32.3 | | 2006 | 30.00374858 | | 2005 | 28.97671243 | | 2004 | 27.02427008 | | 2003 | 25.97176411 | | 2002 | 21.99867548 | | 2001 | 15.38462722 | | 2000 | 7.721411474 | | 1999 | 5.814250962 | | 1998 | 2.724825339 | | 1997 | 1.173174658 | | 1996 | 0.393080525 | | 1995 | 0.158149899 |
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