Year Cases per 100,000 1990 6.28 1991 6.05 1992 5.83 1993 5.63 1994 5.43 1995 5.24 1996 4.85 1997 4.48 1998 4.15 1999 3.84 2000 3.56 2001 3.39 2002 3.23 2003 3.08 2004 2.94 2005 2.8 2006 2.81 2007 2.82 2008 2.83 2009 2.84 2010 2.85 2011 2.89 2012 2.93 2013 2.97 2014 3.01 2015 3.06 2016 3.1