Year Cases per 100,000 1990 15.4 1991 15.39 1992 15.4 1993 15.4 1994 15.4 1995 15.41 1996 15.26 1997 15.12 1998 14.98 1999 14.84 2000 14.71 2001 14.67 2002 14.64 2003 14.61 2004 14.58 2005 14.56 2006 14.86 2007 15.15 2008 15.46 2009 15.78 2010 16.12 2011 16.49 2012 16.89 2013 17.3 2014 17.72 2015 18.16 2016 18.61