Year Cases per 100,000 1990 18.68 1991 18.31 1992 17.83 1993 17.37 1994 16.87 1995 16.5 1996 16.03 1997 15.54 1998 15.1 1999 14.42 2000 13.99 2001 13.48 2002 13.07 2003 12.7 2004 12.15 2005 12.01 2006 11.92 2007 11.89 2008 11.86 2009 11.87 2010 11.77 2011 11.79 2012 11.82 2013 11.75 2014 11.77 2015 11.77 2016 11.79