Year Cases per 100,000 2000 19 2001 16 2002 20 2003 22 2004 20 2005 23 2006 26 2008 21 2009 34 2010 37 2011 23 2012 24 2013 26 2014 26 2015 26 2016 20 2017 23 2018 30 2019 23 2020 18