Year % of adults 2004 7.672641509433963 2005 7.444000000000003 2006 8.41496062992126 2007 11.396062992125986 2008 12.100787401574802 2009 13.76484375 2010 14.5640625 2011 15.972093023255814 2012 16.275757575757577 2013 18.215602836879434 2014 19.033333333333328 2015 20.457042253521138 2016 20.6612676056338 2017 22.04295774647888 2018 24.01126760563381 2019 25.449295774647876