Year Number 1996 0.566771447658539 1998 0.513872742652893 2000 0.398045033216476 2002 0.24177360534668 2003 0.248543098568916 2004 0.428842574357986 2005 0.485128581523895 2006 0.42385545372963 2007 0.566254734992981 2008 0.420968681573868 2009 0.409627974033356 2010 0.325895816087723 2011 0.412495642900467 2012 0.267103314399719 2013 0.278578639030457 2014 0.108568802475929 2015 0.156361043453217 2016 0.153576508164406 2017 0.381892830133438 2018 0.638081014156342 2019 0.546021044254303 2020 0.608559489250183 2021 0.62952595949173 2022 0.56241101026535