Year Cases per 100,000 1990 28.99 1991 28.33 1992 27.69 1993 27.07 1994 26.47 1995 25.9 1996 24.26 1997 22.75 1998 21.33 1999 20.01 2000 18.78 2001 18.93 2002 19.08 2003 19.24 2004 19.4 2005 19.57 2006 19.49 2007 19.4 2008 19.32 2009 19.24 2010 19.18 2011 19.21 2012 19.26 2013 19.3 2014 19.35 2015 19.39 2016 19.45