Year Cases per 100,000 1990 5.15 1991 5.13 1992 5.12 1993 5.09 1994 5.07 1995 5.05 1996 5.03 1997 5 1998 4.98 1999 5 2000 5 2001 4.97 2002 4.94 2003 4.97 2004 5.1 2005 5.18 2006 5.31 2007 5.33 2008 5.21 2009 5.25 2010 5.27 2011 5.36 2012 5.38 2013 5.42 2014 5.47 2015 5.52 2016 5.56