Year Cases per 100,000 1990 22.73 1991 23.62 1992 23.86 1993 23.72 1994 23.45 1995 23.22 1996 23.16 1997 22.45 1998 21.74 1999 21.99 2000 21.9 2001 21.84 2002 22.04 2003 21.2 2004 21.49 2005 21.03 2006 21.18 2007 20.26 2008 20.02 2009 19.81 2010 19.03 2011 18.13 2012 17.71 2013 17.34 2014 16.78 2015 16.38 2016 16.02