| Year | Value | | 2022 | 62.813333227422 | | 2021 | 58.138480437384 | | 2020 | 53.593770714052 | | 2019 | 52.813624618507 | | 2018 | 50.393946353669 | | 2017 | 55.238831093573 | | 2016 | 58.75061809063 | | 2015 | 54.83962507338 | | 2014 | 54.186043427521 | | 2013 | 56.995895885085 | | 2012 | 58.170102102256 | | 2011 | 57.410361343915 | | 2010 | 61.504332184144 | | 2009 | 55.537393943701 | | 2008 | 51.244614009578 | | 2007 | 47.918472011353 | | 2006 | 49.792369145449 |
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