Year % 2000 0.63170761877988 2001 0.649995824936846 2002 0.558450617724469 2003 0.565661381771469 2004 0.562991775367641 2005 0.536577952059319 2006 0.414538367156678 2007 0.385866296574647 2008 0.346434643197232 2009 0.320265575452379 2010 0.30275340346721 2011 0.292628342914722 2012 0.285366258836424 2013 0.281993055221774 2014 0.222719311426845 2015 0.218716650905745 2016 0.212888257702277 2017 0.209593078879474 2018 0.205312271073059 2019 0.207181937319032 2020 0.214637371920403