Year Cases per 100,000 1990 6.32 1991 6.3 1992 6.32 1993 6.37 1994 6.21 1995 6.22 1996 6.21 1997 6.28 1998 6.28 1999 6.08 2000 5.97 2001 5.79 2002 5.76 2003 5.65 2004 5.53 2005 5.34 2006 5.19 2007 5.08 2008 5.03 2009 4.99 2010 4.95 2011 4.88 2012 4.81 2013 4.75 2014 4.69 2015 4.62 2016 4.55