Year Cases per 100,000 1990 8.48 1991 8.33 1992 8 1993 7.72 1994 7.6 1995 7.39 1996 7.2 1997 7.02 1998 6.87 1999 6.65 2000 6.47 2001 6.31 2002 6.17 2003 6.05 2004 5.96 2005 5.88 2006 5.82 2007 5.76 2008 5.74 2009 5.7 2010 5.66 2011 5.6 2012 5.53 2013 5.46 2014 5.38 2015 5.3 2016 5.2