Year Cases per 100,000 1953 0.28 1954 0.28 1955 0.57 1956 0.42 1957 0.43 1958 0.52 1959 0.37 1960 0.46 1961 0.65 1962 0.55 1963 0.89 1964 0.46 1965 0.3 1966 0.4 1967 0.45 1968 0.92 1969 0.52 1970 0.75 1971 0.946 1972 1.152 1973 0.778 1974 0.914 1975 0.62 1976 0.836 1977 0.862 1978 0.918 1979 0.994 1980 1.1 1981 1.106 1982 1.052 1983 0.928 1984 1.234 1985 1.44 1986 1.166 1987 0.802 1988 0.958 1989 1.134 1990 1.24 1991 1.24 1992 1.24 1993 1.23 1994 1.23 1995 1.23 1996 1.26 1997 1.29 1998 1.32 1999 1.36 2000 1.39 2001 1.44 2002 1.5 2003 1.55 2004 1.61 2005 1.67 2006 1.73 2007 1.8 2008 1.87 2009 1.94 2010 2.02 2011 2.03 2012 2.05 2013 2.07 2014 2.09 2015 2.11 2016 2.13