Year Number 1996 0.561770856380463 1998 0.617432355880737 2000 0.556891262531281 2002 0.674292743206024 2003 0.656516373157501 2004 0.456370502710342 2005 0.45884957909584 2006 0.551547348499298 2007 0.600704789161682 2008 0.613664507865906 2009 0.755774736404419 2010 0.786790609359741 2011 0.731594443321228 2012 0.614688694477081 2013 0.576835691928864 2014 0.76191633939743 2015 0.737417757511139 2016 0.619399189949036 2017 0.556687533855438 2018 0.570794284343719 2019 0.603662550449371 2020 0.648838937282562 2021 0.698169112205505 2022 0.767688930034637