Year Percent 2000 63 2001 66 2002 70 2003 70 2004 75 2005 69 2006 60 2007 62 2008 69 2009 68 2010 62 2011 70 2012 69 2013 67 2014 72 2015 70 2016 69 2017 68 2018 65 2019 71 2020 64