Year Cases per 100,000 1990 6.07 1991 6.05 1992 6.03 1993 6.01 1994 6 1995 5.98 1996 5.88 1997 5.78 1998 5.69 1999 5.6 2000 5.51 2001 5.45 2002 5.4 2003 5.35 2004 5.3 2005 5.25 2006 5.22 2007 5.2 2008 5.17 2009 5.15 2010 5.13 2011 5.17 2012 5.22 2013 5.26 2014 5.31 2015 5.36 2016 5.41