Year % of adults 2004 2.7220779220779217 2005 2.8399999999999994 2006 3.6065934065934058 2007 4.286813186813185 2008 5.6549450549450535 2009 7.25217391304348 2010 8.184782608695654 2011 9.043478260869565 2012 10.085106382978722 2013 11.287254901960782 2014 11.546078431372548 2015 13.332352941176469 2016 13.395098039215686 2017 14.050980392156868 2018 14.904901960784315 2019 15.10392156862745