| Year | Value | | 2021 | 52.9734788 | | 2020 | 48.76420428 | | 2019 | 44.8268148 | | 2018 | 40 | | 2017 | 36.83740647 | | 2016 | 31.03334594 | | 2015 | 25.68785182 | | 2014 | 14.84 | | 2013 | 13.9 | | 2012 | 12.9414 | | 2011 | 12 | | 2010 | 11.6 | | 2009 | 6.5 | | 2008 | 5.329003772 | | 2007 | 4.835610778 | | 2006 | 4.398870647 | | 2005 | 4.010046644 | | 2004 | 3.804715615 | | 2003 | 3.359839886 | | 2002 | 2.633699769 | | 2001 | 2.416979442 | | 2000 | 1.644739547 | | 1999 | 0.336217708 | | 1998 | 0.286745093 | | 1997 | 0.058750679 | | 1996 | 0.009032145 | | 1995 | 0.006172051 |
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