Year Cases per 100,000 1983 5.88375 1984 6.0775 1985 6.42125 1986 6.375 1987 7.41875 1988 8.0225 1989 8.96625 1990 8.67 1991 8.83 1992 8.99 1993 9.15 1994 9.33 1995 9.51 1996 9.5 1997 9.5 1998 9.5 1999 9.49 2000 9.5 2001 9.38 2002 9.27 2003 9.17 2004 9.07 2005 8.97 2006 8.93 2007 8.89 2008 8.86 2009 8.82 2010 8.8 2011 8.66 2012 8.53 2013 8.4 2014 8.28 2015 8.16 2016 8.04