Year Cases per 100,000 1990 4.48 1991 4.47 1992 4.46 1993 4.46 1994 4.46 1995 4.46 1996 4.45 1997 4.44 1998 4.43 1999 4.42 2000 4.42 2001 4.39 2002 4.36 2003 4.33 2004 4.31 2005 4.29 2006 4.29 2007 4.28 2008 4.28 2009 4.28 2010 4.29 2011 4.28 2012 4.28 2013 4.27 2014 4.27 2015 4.26 2016 4.27