Year Cases per 100,000 1990 6.05 1991 6.04 1992 6.03 1993 6.02 1994 6.02 1995 6.02 1996 5.97 1997 5.92 1998 5.88 1999 5.83 2000 5.79 2001 5.8 2002 5.82 2003 5.83 2004 5.84 2005 5.86 2006 5.9 2007 5.94 2008 5.98 2009 6.03 2010 6.08 2011 6.11 2012 6.14 2013 6.17 2014 6.2 2015 6.23 2016 6.27