Year per 1,000 adults 2006 6.52 2007 7.36 2008 8.16 2009 9.11 2010 10.35 2011 11.81 2012 13.26 2013 14.93 2014 16.95 2015 19.21 2016 22.11 2017 25.37 2018 28.97 2019 32.97 2020 36.21 2021 39.79