Year Cases per 100,000 1990 6.19 1991 6.19 1992 6.19 1993 6.18 1994 6.18 1995 6.18 1996 6.01 1997 5.84 1998 5.68 1999 5.52 2000 5.38 2001 5.36 2002 5.36 2003 5.35 2004 5.35 2005 5.35 2006 5.3 2007 5.26 2008 5.22 2009 5.18 2010 5.15 2011 5.14 2012 5.14 2013 5.13 2014 5.13 2015 5.13 2016 5.12