Year Cases per 100,000 2000 32 2001 31 2002 31 2003 28 2004 30 2005 27 2006 25 2007 26 2008 23 2009 19 2010 18 2011 24 2012 21 2013 21 2014 22 2015 22 2016 24 2017 23 2018 23 2019 26 2020 21