Year Cases per 100,000 1990 5.95 1991 5.82 1992 5.77 1993 5.89 1994 5.96 1995 6.06 1996 5.91 1997 5.61 1998 5.33 1999 5.14 2000 5.07 2001 4.95 2002 4.86 2003 4.72 2004 4.62 2005 4.48 2006 4.47 2007 4.41 2008 4.43 2009 4.42 2010 4.37 2011 4.24 2012 4.12 2013 4.01 2014 3.9 2015 3.81 2016 3.72