Year % of adults 2004 0 2005 0 2006 0.2 2007 0.2 2008 0.2 2009 0.2 2010 0.2 2011 0.3 2012 2.3 2013 2.4 2014 2 2015 1.9 2016 3 2017 2.9 2018 3.2 2019 3.6