| Year | Value | | 2022 | 26.41509437561 | | 2021 | 20.754716873169 | | 2020 | 13.679244995117 | | 2019 | 13.679244995117 | | 2018 | 15.566038131714 | | 2017 | 12.857142448425 | | 2016 | 15.714285850525 | | 2015 | 20 | | 2014 | 13.333333015442 | | 2013 | 17.061611175537 | | 2012 | 11.848340988159 | | 2011 | 8.5308055877685 | | 2010 | 8.0568723678589 | | 2009 | 11.374407768249 | | 2008 | 7.2115383148193 | | 2007 | 6.2801933288574 | | 2006 | 4.8309178352356 | | 2005 | 0.97087377309799 | | 2004 | 3.3980581760406 | | 2003 | 5.02512550354 | | 2002 | 3.1746032238007 | | 2000 | 13.227513313293 | | 1998 | 36.170211791992 | | 1996 | 48.936168670654 |
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