Year Cases per 100,000 1990 4.6 1991 4.62 1992 4.64 1993 4.65 1994 4.67 1995 4.69 1996 4.7 1997 4.7 1998 4.71 1999 4.71 2000 4.72 2001 4.66 2002 4.6 2003 4.55 2004 4.49 2005 4.44 2006 4.39 2007 4.33 2008 4.28 2009 4.22 2010 4.17 2011 4.18 2012 4.18 2013 4.19 2014 4.2 2015 4.2 2016 4.21