Year Cases per 100,000 1990 2.48 1991 2.28 1992 2.1 1993 1.94 1994 1.79 1995 1.65 1996 1.6 1997 1.56 1998 1.51 1999 1.47 2000 1.43 2001 1.43 2002 1.43 2003 1.42 2004 1.42 2005 1.42 2006 1.43 2007 1.44 2008 1.46 2009 1.47 2010 1.48 2011 1.49 2012 1.5 2013 1.51 2014 1.52 2015 1.53 2016 1.54