Year % of adults 2004 9 2005 8.7 2006 10.6 2007 11 2008 9.7 2009 10.9 2010 13.9 2011 15.7 2012 16.7 2013 20.9 2014 22.8 2015 23.1 2016 24.4 2017 25.4 2018 24.4 2019 23.9