Year Cases per 100,000 1990 4.05 1991 4 1992 3.95 1993 3.89 1994 3.84 1995 3.8 1996 3.8 1997 3.8 1998 3.81 1999 3.81 2000 3.82 2001 3.86 2002 3.91 2003 3.96 2004 4.01 2005 4.06 2006 4.09 2007 4.12 2008 4.15 2009 4.18 2010 4.21 2011 4.24 2012 4.27 2013 4.3 2014 4.33 2015 4.36 2016 4.4