Year % 2000 3.38871867813096 2001 3.16077057982207 2002 2.93433521450343 2003 2.68435499382286 2004 2.35517190123672 2005 2.14476776380639 2006 1.93455084209698 2007 2.09186489719229 2008 2.49688471375723 2009 2.69745248375176 2010 2.93046010500624 2011 2.6996781714745 2012 2.75900925018527 2013 2.46246948268234 2014 2.32935872832156 2015 2.19740320783212 2016 2.13539847515958 2017 1.74420161755893 2018 1.82336636266784 2019 1.73121239776876 2020 1.65369760831923