Year per 1,000 adults 2004 3.95 2005 6.33 2006 8.63 2007 11.97 2008 14.39 2009 17.25 2010 22.02 2011 26.73 2012 31.38 2013 32.95 2014 33.31 2015 39.06 2016 40.09 2017 34.48 2018 37.62 2019 50 2020 48.1 2021 51.06