Year Cases per 100,000 1990 9.38 1991 9.23 1992 9.07 1993 8.62 1994 8.14 1995 7.67 1996 7.43 1997 7.25 1998 7.17 1999 7.19 2000 7.2 2001 7.05 2002 6.82 2003 6.54 2004 6.29 2005 6.04 2006 5.77 2007 5.57 2008 5.41 2009 5.23 2010 5.12 2011 5.09 2012 5 2013 4.77 2014 4.62 2015 4.57 2016 4.55