Year % of adults 2004 0.38 2005 0.4600000000000001 2006 0.64 2007 0.62 2008 1.7799999999999998 2009 2.9200000000000004 2010 3.7800000000000002 2011 5.9399999999999995 2012 6.82 2013 7.7 2014 11.3 2015 12.7 2016 14.024999999999999 2017 14.100000000000001 2018 18.525 2019 21.0375