Year Cases per 100,000 1990 3.82 1991 3.73 1992 3.65 1993 3.56 1994 3.48 1995 3.4 1996 3.38 1997 3.36 1998 3.34 1999 3.32 2000 3.3 2001 3.18 2002 3.07 2003 2.95 2004 2.85 2005 2.74 2006 2.69 2007 2.64 2008 2.59 2009 2.54 2010 2.49 2011 2.5 2012 2.51 2013 2.53 2014 2.54 2015 2.55 2016 2.56