Year Cases per 100,000 1990 4.93 1991 4.84 1992 4.9 1993 4.66 1994 4.7 1995 4.49 1996 4.71 1997 5.28 1998 5.34 1999 5.36 2000 5.42 2001 5.14 2002 5 2003 4.9 2004 4.79 2005 4.77 2006 4.74 2007 4.62 2008 4.48 2009 4.4 2010 4.33 2011 4.22 2012 4.02 2013 3.86 2014 3.79 2015 3.72 2016 3.69