Year Cases per 100,000 1990 4.56 1991 4.59 1992 4.62 1993 4.65 1994 4.68 1995 4.72 1996 4.75 1997 4.78 1998 4.81 1999 4.85 2000 4.89 2001 4.85 2002 4.81 2003 4.78 2004 4.74 2005 4.71 2006 4.65 2007 4.58 2008 4.52 2009 4.46 2010 4.41 2011 4.37 2012 4.34 2013 4.31 2014 4.28 2015 4.25 2016 4.22