Year Cases per 100,000 1990 2.99 1991 2.95 1992 2.92 1993 2.89 1994 2.85 1995 2.82 1996 2.81 1997 2.81 1998 2.8 1999 2.8 2000 2.8 2001 2.78 2002 2.77 2003 2.76 2004 2.74 2005 2.73 2006 2.69 2007 2.64 2008 2.6 2009 2.56 2010 2.52 2011 2.53 2012 2.54 2013 2.55 2014 2.56 2015 2.58 2016 2.59