Year Cases per 100,000 1963 48.61 1964 45.9 1965 41.07 1966 45.25 1967 43.41 1968 42.75 1969 40.85 1970 41.85 1971 42.9125 1972 39.075 1973 44.1175 1974 46.21 1975 42.9825 1976 46.615 1977 42.2675 1978 43 1979 44.6425 1980 39.975 1981 40.6575 1982 39.38 1983 37.1725 1984 37.855 1985 38.9475 1986 39.71 1987 36.8225 1988 41.365 1989 41.6975 1990 40.3 1991 39.62 1992 39.12 1993 39.16 1994 37.81 1995 36.7 1996 35.27 1997 35.13 1998 34.38 1999 33.33 2000 32.03 2001 31.16 2002 30.27 2003 29.44 2004 28.48 2005 27.12 2006 26.26 2007 25.39 2008 24.47 2009 23.62 2010 22.94 2011 21.98 2012 21.44 2013 21.04 2014 20.19 2015 20.54 2016 20.47