| Year | Value | | 2021 | 28.75752799 | | 2020 | 25.53293999 | | 2019 | 22.66877336 | | 2018 | 19.5 | | 2017 | 17.82710021 | | 2016 | 16.6 | | 2015 | 16.58785485 | | 2014 | 16.5 | | 2013 | 13 | | 2012 | 10.5 | | 2011 | 8.8 | | 2010 | 7.2 | | 2009 | 6.1 | | 2008 | 5.2 | | 2007 | 4.4 | | 2006 | 3.6 | | 2005 | 3.101897702 | | 2004 | 3.023528042 | | 2003 | 2.941902861 | | 2002 | 1.207773885 | | 2001 | 0.619782266 | | 2000 | 0.318059714 | | 1999 | 0.114256028 | | 1998 | 0.050261388 | | 1997 | 0.034406051 | | 1996 | 0.008839115 | | 1995 | 0.000727482 |
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