Year Cases per 100,000 1983 2.1175 1984 2.785 1985 2.5925 1986 2.71 1987 2.9875 1988 3.235 1989 3.5225 1990 3.92 1991 3.97 1992 4.02 1993 4.07 1994 4.13 1995 4.18 1996 4.14 1997 4.11 1998 4.07 1999 4.03 2000 4 2001 3.95 2002 3.9 2003 3.86 2004 3.81 2005 3.77 2006 3.7 2007 3.64 2008 3.58 2009 3.52 2010 3.46 2011 3.41 2012 3.36 2013 3.31 2014 3.26 2015 3.21 2016 3.17