Year Cases per 100,000 1990 5.3 1991 5.35 1992 5.41 1993 5.48 1994 5.54 1995 5.61 1996 5.52 1997 5.43 1998 5.34 1999 5.25 2000 5.17 2001 5.26 2002 5.34 2003 5.43 2004 5.52 2005 5.61 2006 5.59 2007 5.56 2008 5.54 2009 5.52 2010 5.5 2011 5.45 2012 5.4 2013 5.36 2014 5.31 2015 5.26 2016 5.22