Year Cases per 100,000 1990 5.16 1991 5.07 1992 4.98 1993 4.89 1994 4.8 1995 4.72 1996 4.59 1997 4.48 1998 4.36 1999 4.25 2000 4.15 2001 4.11 2002 4.08 2003 4.05 2004 4.02 2005 3.99 2006 4.01 2007 4.03 2008 4.04 2009 4.06 2010 4.08 2011 4.1 2012 4.12 2013 4.13 2014 4.15 2015 4.17 2016 4.19