Year Cases per 100,000 1990 3.58 1991 3.58 1992 3.59 1993 3.6 1994 3.61 1995 3.63 1996 3.61 1997 3.6 1998 3.59 1999 3.58 2000 3.57 2001 3.55 2002 3.54 2003 3.53 2004 3.52 2005 3.51 2006 3.48 2007 3.45 2008 3.43 2009 3.4 2010 3.38 2011 3.36 2012 3.33 2013 3.31 2014 3.29 2015 3.27 2016 3.25