Year Cases per 100,000 1958 2.02 1959 1.24 1961 1.63 1962 0.9 1964 1.06 1965 0.62 1966 1.59 1968 3.72 1969 1.8 1970 4.5195 1971 0.599 1972 1.5485 1973 0.928 1975 0.9475 1976 1.407 1977 2.2665 1978 1.996 1979 1.1955 1980 2.735 1981 4.3045 1982 3.024 1983 1.8535 1984 2.863 1985 1.8225 1986 2.352 1987 2.4015 1988 3.621 1989 2.9005 1990 1.54 1991 1.58 1992 1.62 1993 1.67 1994 1.71 1995 1.76 1996 1.8 1997 1.83 1998 1.87 1999 1.91 2000 1.95 2001 2 2002 2.05 2003 2.1 2004 2.15 2005 2.21 2006 2.24 2007 2.28 2008 2.32 2009 2.36 2010 2.4 2011 2.48 2012 2.57 2013 2.65 2014 2.74 2015 2.83 2016 2.93