Year % of adults 2004 0.9902439024390244 2005 1.5760869565217388 2006 1.8478260869565215 2007 2.35 2008 2.7826086956521747 2009 3.217391304347826 2010 3.4456521739130435 2011 3.9347826086956528 2012 4.570212765957447 2013 4.682352941176472 2014 4.545098039215685 2015 5.133333333333334 2016 5.317647058823529 2017 5.7215686274509805 2018 6.5509803921568635 2019 7.723529411764707