Year Percent 2000 12 2001 16 2002 22 2003 29 2004 36 2005 40 2006 46 2007 49 2008 47 2009 49 2010 52 2011 56 2012 61 2013 60 2014 64 2015 67 2016 70 2017 69 2018 76 2019 77 2020 62