Year Cases per 100,000 1990 1.5 1991 1.65 1992 1.81 1993 2 1994 2.2 1995 2.42 1996 2.6 1997 2.79 1998 2.99 1999 3.22 2000 3.46 2001 3.41 2002 3.38 2003 3.34 2004 3.3 2005 3.26 2006 3.29 2007 3.3 2008 3.33 2009 3.35 2010 3.37 2011 3.37 2012 3.36 2013 3.36 2014 3.35 2015 3.35 2016 3.35