Year Cases per 100,000 1990 21.79 1991 21.65 1992 21.57 1993 21.44 1994 21.38 1995 21.31 1996 20.77 1997 20.03 1998 19.4 1999 19.03 2000 18.72 2001 18.19 2002 17.58 2003 16.94 2004 16.26 2005 15.8 2006 15.4 2007 14.93 2008 14.74 2009 14.78 2010 14.9 2011 15.28 2012 15.49 2013 15.69 2014 16.02 2015 16.62 2016 17.34