Year % of adults 2004 3.3354166666666676 2005 3.284662576687117 2006 3.8964071856287434 2007 4.241764705882354 2008 5.219883040935671 2009 6.440116279069768 2010 7.14011627906977 2011 8.20747126436782 2012 9.007303370786516 2013 10.2026455026455 2014 10.471428571428568 2015 11.777894736842104 2016 12.583157894736841 2017 13.989473684210529 2018 15.33298429319372 2019 15.796858638743464