Year Cases per 100,000 1990 26.47 1991 26.84 1992 27.24 1993 27.64 1994 28.05 1995 28.48 1996 28.24 1997 28.02 1998 27.81 1999 27.6 2000 27.41 2001 26.81 2002 26.25 2003 25.71 2004 25.18 2005 24.68 2006 24.48 2007 24.26 2008 24.07 2009 23.88 2010 23.7 2011 23.54 2012 23.4 2013 23.25 2014 23.11 2015 22.97 2016 22.84