Year Cases per 100,000 1990 4.88 1991 4.88 1992 4.88 1993 4.88 1994 4.88 1995 4.88 1996 4.84 1997 4.81 1998 4.77 1999 4.74 2000 4.7 2001 4.69 2002 4.68 2003 4.68 2004 4.67 2005 4.66 2006 4.72 2007 4.78 2008 4.84 2009 4.91 2010 4.97 2011 5.01 2012 5.06 2013 5.1 2014 5.14 2015 5.19 2016 5.23