Year Cases per 100,000 2000 43 2001 28 2002 29 2003 17 2004 26 2005 20 2006 21 2007 19 2008 20 2009 22 2010 19 2011 20 2012 15 2014 11 2015 21 2016 14 2017 12 2018 13 2019 8.1 2020 15