Year Cases per 100,000 1990 6.82 1991 6.91 1992 6.92 1993 7.08 1994 7.12 1995 7.18 1996 6.46 1997 5.91 1998 5.45 1999 5.18 2000 4.9 2001 4.58 2002 4.79 2003 4.86 2004 4.77 2005 4.61 2006 4.49 2007 4.3 2008 4.25 2009 4.11 2010 3.94 2011 3.88 2012 3.86 2013 3.75 2014 3.82 2015 3.8 2016 3.82