Year Cases per 100,000 1990 8.87 1991 8.6 1992 8.34 1993 8.1 1994 7.86 1995 7.63 1996 6.89 1997 6.21 1998 5.61 1999 5.06 2000 4.57 2001 4.38 2002 4.19 2003 4.02 2004 3.85 2005 3.69 2006 3.79 2007 3.89 2008 3.99 2009 4.1 2010 4.21 2011 4.25 2012 4.3 2013 4.35 2014 4.4 2015 4.45 2016 4.5