Year Cases per 100,000 1990 2.44 1991 2.47 1992 2.5 1993 2.53 1994 2.57 1995 2.6 1996 2.63 1997 2.65 1998 2.68 1999 2.71 2000 2.74 2001 2.74 2002 2.74 2003 2.74 2004 2.74 2005 2.74 2006 2.73 2007 2.71 2008 2.7 2009 2.68 2010 2.67 2011 2.67 2012 2.68 2013 2.68 2014 2.68 2015 2.68 2016 2.69