Year % of adults 2004 0.6 2005 0.6 2006 0.5 2007 0.7 2008 0.7 2009 0.8 2010 1 2011 1.3 2012 1.3 2013 0 2014 1.3 2015 1.6 2016 1.9 2017 1.9 2018 2 2019 1.8