| Year | Value | | 2023 | 13.744075775147 | | 2022 | 13.679244995117 | | 2021 | 11.792452812195 | | 2020 | 12.735849380493 | | 2019 | 9.9056606292725 | | 2018 | 10.377358436584 | | 2017 | 7.1428570747375 | | 2016 | 4.7619047164917 | | 2015 | 9.0476188659668 | | 2014 | 11.904762268066 | | 2013 | 10.900473594666 | | 2012 | 12.796208381653 | | 2011 | 18.48341178894 | | 2010 | 18.957345962524 | | 2009 | 15.639810562134 | | 2008 | 18.75 | | 2007 | 19.806762695312 | | 2006 | 27.053140640259 | | 2005 | 27.669902801514 | | 2004 | 20.873786926269 | | 2003 | 25.1256275177 | | 2002 | 21.693120956421 | | 2000 | 21.16402053833 | | 1998 | 12.234042167664 | | 1996 | 10.638298034668 |
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