Year Cases per 100,000 1980 28.55364 1981 23.81727 1982 22.37091 1983 25.19455 1984 23.13818 1985 26.35182 1986 23.00545 1987 24.61909 1988 22.93273 1989 24.63636 1990 24.37 1991 24.06 1992 23.45 1993 23.16 1994 22.45 1995 22 1996 21.3 1997 20.04 1998 19.53 1999 18.65 2000 17.84 2001 17.23 2002 16.35 2003 15.5 2004 15.1 2005 14.39 2006 13.75 2007 13.23 2008 13.2 2009 13.04 2010 13.02 2011 12.88 2012 13.11 2013 13.06 2014 13.02 2015 13.19 2016 13.25