Year % of adults 2004 0 2005 0.1 2006 0.1 2007 0.1 2008 0.1 2009 0.2 2010 0.3 2011 0.7 2012 0.9 2013 1 2014 1.2 2015 1.3 2016 1.3 2017 1.3 2018 1.3 2019 1.3