Year % of adults 2004 0.8 2005 1.1 2006 2.7 2007 9.2 2008 13.4 2009 19 2010 26.4 2011 29.8 2012 37.8 2013 39.1 2014 41.8 2015 41.5 2016 41.8 2017 51 2018 54.8 2019 59.4