Year per 1,000 adults 2004 7.71 2005 7.24 2006 5.85 2007 5.68 2008 5.61 2009 6.31 2010 4.54 2011 8.91 2012 9.9 2013 10.82 2014 9.68 2015 10.33 2016 11.45 2017 13.18 2018 14.6 2019 14.62 2020 15.19 2021 15.84