Year Cases per 100,000 1990 3.15 1991 3.11 1992 3.07 1993 3.04 1994 3 1995 2.97 1996 2.92 1997 2.88 1998 2.84 1999 2.81 2000 2.78 2001 2.74 2002 2.71 2003 2.67 2004 2.64 2005 2.61 2006 2.63 2007 2.65 2008 2.68 2009 2.7 2010 2.73 2011 2.74 2012 2.75 2013 2.76 2014 2.76 2015 2.77 2016 2.78