Year Cases per 100,000 1990 35.3 1991 35.95 1992 35.74 1993 35.02 1994 33.85 1995 32.7 1996 32.35 1997 31.24 1998 30.39 1999 30.45 2000 30.22 2001 29.61 2002 29.38 2003 27.89 2004 27.7 2005 26.87 2006 27.03 2007 25.97 2008 25.68 2009 25.49 2010 24.72 2011 23.91 2012 23.85 2013 23.76 2014 23.75 2015 23.88 2016 24