Year Cases per 100,000 2000 25 2002 33 2003 34 2004 29 2005 36 2006 34 2007 35 2008 33 2009 34 2011 24 2012 25 2013 21 2014 18 2015 15 2016 17 2017 21 2018 27 2019 33 2020 25