Year Cases per 100,000 1983 3.03 1984 2.45 1985 2.43 1986 3.04 1987 3.6 1988 3.71 1989 2.93 1990 3.43 1991 3.6 1992 3.77 1993 3.96 1994 4.15 1995 4.36 1996 4.55 1997 4.74 1998 4.95 1999 5.17 2000 5.41 2001 5.63 2002 5.88 2003 6.13 2004 6.4 2005 6.68 2006 6.85 2007 7.03 2008 7.22 2009 7.41 2010 7.61 2011 7.75 2012 7.89 2013 8.03 2014 8.18 2015 8.33 2016 8.49