Year Percent 2000 9.6 2001 17 2002 14 2003 15 2004 19 2005 21 2006 23 2007 26 2008 26 2009 26 2010 24 2011 24 2012 25 2013 25 2014 22 2015 22 2016 24 2017 24 2018 24 2019 27 2020 30