Year Cases per 100,000 1990 4.78 1991 4.79 1992 4.79 1993 4.8 1994 4.8 1995 4.81 1996 4.81 1997 4.82 1998 4.83 1999 4.84 2000 4.85 2001 4.79 2002 4.73 2003 4.67 2004 4.62 2005 4.57 2006 4.52 2007 4.47 2008 4.42 2009 4.38 2010 4.33 2011 4.34 2012 4.35 2013 4.37 2014 4.38 2015 4.39 2016 4.4