Year % of adults 2005 11.9 2006 11.9 2007 20.3 2008 21.8 2009 23 2010 22.1 2011 20.2 2012 19.7 2013 17.3 2014 16.7 2015 17.8 2016 20 2017 19.6 2018 19.9 2019 20