Year Cases per 100,000 1990 24.18 1991 23.92 1992 23.69 1993 23.46 1994 23.23 1995 23.03 1996 22.67 1997 22.33 1998 22 1999 21.67 2000 21.37 2001 21.09 2002 20.83 2003 20.58 2004 20.33 2005 20.09 2006 20.02 2007 19.94 2008 19.87 2009 19.8 2010 19.74 2011 19.73 2012 19.74 2013 19.74 2014 19.74 2015 19.75 2016 19.77