Year Cases per 100,000 1990 18.32 1991 18.63 1992 18.95 1993 19.29 1994 19.62 1995 19.98 1996 20.12 1997 20.27 1998 20.42 1999 20.57 2000 20.75 2001 20.54 2002 20.35 2003 20.17 2004 19.98 2005 19.82 2006 19.75 2007 19.67 2008 19.61 2009 19.54 2010 19.5 2011 19.42 2012 19.36 2013 19.3 2014 19.25 2015 19.19 2016 19.15