Year Cases per 100,000 2000 4.8 2001 4.5 2002 3.9 2003 4.4 2004 4.3 2005 3.3 2006 3.4 2007 3.8 2008 3.8 2009 5 2010 4.6 2011 3.7 2012 3.2 2013 3.4 2014 3 2015 3.6 2016 3.5 2017 4.1 2018 2.8 2019 2.5 2020 2.1