Year Cases per 100,000 1990 20.24 1991 19.91 1992 19.56 1993 19.19 1994 18.84 1995 18.46 1996 18.07 1997 17.67 1998 17.32 1999 16.91 2000 16.62 2001 16.39 2002 15.9 2003 15.63 2004 15.32 2005 15.06 2006 14.79 2007 14.47 2008 14.16 2009 13.83 2010 13.49 2011 13.11 2012 12.84 2013 12.58 2014 12.28 2015 12 2016 11.77