Year % of adults 2004 0 2005 2.6 2006 1.5 2007 2.8 2008 2.6 2009 4.4 2010 16.9 2011 23.7 2012 20.5 2013 21.9 2014 23.5 2015 0 2016 0 2017 0 2018 0 2019 0