Year Cases per 100,000 1990 4.26 1991 4.24 1992 4.22 1993 4.2 1994 4.18 1995 4.17 1996 4.16 1997 4.16 1998 4.16 1999 4.15 2000 4.15 2001 4.29 2002 4.43 2003 4.57 2004 4.72 2005 4.87 2006 4.83 2007 4.78 2008 4.73 2009 4.68 2010 4.64 2011 4.64 2012 4.65 2013 4.65 2014 4.66 2015 4.67 2016 4.68