Year Cases per 100,000 1990 9.63 1991 9.3 1992 8.99 1993 8.7 1994 8.41 1995 8.14 1996 7.84 1997 7.55 1998 7.28 1999 7.01 2000 6.77 2001 6.57 2002 6.38 2003 6.2 2004 6.03 2005 5.87 2006 5.7 2007 5.53 2008 5.37 2009 5.22 2010 5.08 2011 4.91 2012 4.76 2013 4.61 2014 4.47 2015 4.33 2016 4.2