Year % of adults 2004 0 2005 0 2006 0 2007 0 2008 2.2 2009 2.1 2010 3.3 2011 3.6 2012 15.7 2013 16.5 2014 17.8 2015 19.4 2016 27.8 2017 40.1 2018 42.7 2019 47.8