Year Cases per 100,000 2000 8.1 2001 7.6 2002 8.2 2003 7.9 2004 7.5 2005 7 2006 6.3 2007 5.6 2008 6.1 2009 6.5 2010 6.5 2011 6.6 2012 5.2 2013 5.7 2014 5.2 2015 6.4 2016 6.8 2017 6.3 2018 5.5 2019 4.7 2020 4.1