Year % of adults 2004 0.3 2005 3.5 2006 3.6 2007 2.7 2008 2.6 2009 2.7 2010 2.5 2011 2.5 2012 2.8 2013 3.1 2014 3 2015 0.5 2016 0.5 2017 0.6 2018 0.6 2019 0