Year Cases per 100,000 1990 3.06 1991 3.06 1992 3.07 1993 3.08 1994 3.09 1995 3.1 1996 3.22 1997 3.36 1998 3.5 1999 3.64 2000 3.8 2001 3.96 2002 4.13 2003 4.3 2004 4.49 2005 4.68 2006 4.64 2007 4.6 2008 4.56 2009 4.52 2010 4.48 2011 4.46 2012 4.44 2013 4.42 2014 4.41 2015 4.39 2016 4.38