Year Number 1996 0.837555170059204 1998 0.736908495426178 2000 0.587037920951843 2002 0.776045680046082 2003 0.703846335411072 2004 0.785955905914307 2005 0.709748506546021 2006 0.629231572151184 2007 0.551828980445862 2008 0.577969372272491 2009 0.615196585655212 2010 0.492912799119949 2011 0.451953709125519 2012 0.276448935270309 2013 0.357710689306259 2014 0.298648625612259 2015 0.146552965044975 2016 0.125311464071274 2017 0.239429265260696 2018 0.258635640144348 2019 0.31449168920517 2020 0.403194963932037 2021 0.406721621751785 2022 0.447398781776428