| Year | Value | | 2021 | 30.46181693 | | 2020 | 23.8 | | 2019 | 21.35801007 | | 2018 | 19.2 | | 2017 | 17.2 | | 2016 | 14.6 | | 2015 | 12.5 | | 2014 | 10.6 | | 2013 | 9 | | 2012 | 8.023854277 | | 2011 | 7 | | 2010 | 8 | | 2009 | 7.7 | | 2008 | 4.5 | | 2007 | 2.115387178 | | 2005 | 0.556041165 | | 2004 | 0.430854243 | | 2003 | 0.356918467 | | 2002 | 0.292784719 | | 2001 | 0.24067241 | | 2000 | 0.06283146 | | 1999 | 0.067176482 | | 1998 | 0.011763573 | | 1997 | 0.001625791 | | 1996 | 0.000883372 |
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