Year Cases per 100,000 1990 6.62 1991 6.56 1992 6.64 1993 6.67 1994 6.8 1995 6.86 1996 6.82 1997 6.85 1998 6.91 1999 6.71 2000 6.43 2001 6.08 2002 5.77 2003 5.68 2004 5.5 2005 5.36 2006 5.2 2007 5.1 2008 4.98 2009 4.9 2010 4.79 2011 4.69 2012 4.61 2013 4.58 2014 4.52 2015 4.44 2016 4.34