Year Percent 2000 18 2001 25 2002 32 2003 31 2004 39 2005 45 2006 51 2007 56 2008 54 2009 49 2010 51 2011 49 2012 49 2013 50 2014 50 2015 55 2016 63 2017 68 2018 69 2019 73 2020 61