Year Cases per 100,000 1990 3.76 1991 3.76 1992 3.76 1993 3.76 1994 3.76 1995 3.77 1996 3.78 1997 3.8 1998 3.83 1999 3.9 2000 3.98 2001 4.03 2002 4.08 2003 4.13 2004 4.18 2005 4.21 2006 4.28 2007 4.35 2008 4.42 2009 4.5 2010 4.56 2011 4.6 2012 4.63 2013 4.66 2014 4.69 2015 4.72 2016 4.75