Year Cases per 100,000 1990 4.7 1991 4.7 1992 4.65 1993 4.72 1994 4.65 1995 4.66 1996 4.59 1997 4.55 1998 4.54 1999 4.51 2000 4.46 2001 4.4 2002 4.37 2003 4.34 2004 4.32 2005 4.29 2006 4.27 2007 4.25 2008 4.22 2009 4.19 2010 4.16 2011 4.14 2012 4.11 2013 4.07 2014 4.03 2015 3.99 2016 3.94