Year Cases per 100,000 1990 24.13 1991 24.25 1992 24.38 1993 24.52 1994 24.65 1995 24.8 1996 24.46 1997 24.15 1998 23.84 1999 23.54 2000 23.26 2001 22.73 2002 22.23 2003 21.75 2004 21.28 2005 20.84 2006 20.63 2007 20.42 2008 20.22 2009 20.02 2010 19.84 2011 19.72 2012 19.61 2013 19.51 2014 19.4 2015 19.3 2016 19.21