Year % of adults 2004 2.1804123711340204 2005 2.39375 2006 3.0008771929824554 2007 3.530701754385964 2008 4.649122807017543 2009 5.945217391304348 2010 6.700869565217393 2011 7.438260869565216 2012 8.263559322033899 2013 9.40793650793651 2014 9.67936507936508 2015 10.996062992125982 2016 11.07244094488189 2017 11.649606299212595 2018 12.365354330708659 2019 12.605511811023625