Year % of adults 2004 1.6 2005 2.1 2006 2.5 2007 6.1 2008 14.6 2009 24.3 2010 23.3 2011 25.5 2012 28.3 2013 25.4 2014 27.4 2015 27.5 2016 30.5 2017 32.2 2018 34.5 2019 36.4