Year Cases per 100,000 1968 6.17 1969 6.63 1970 4.64 1971 6.0905 1972 5.171 1973 6.4115 1974 6.132 1975 7.0425 1976 7.453 1977 7.6135 1978 7.234 1979 7.5145 1980 7.515 1981 8.0355 1982 7.296 1983 8.4965 1984 8.007 1985 9.4875 1986 9.618 1987 9.9985 1988 10.969 1989 10.7395 1990 10.49 1991 10.99 1992 11.01 1993 11.44 1994 11.47 1995 11.16 1996 10.79 1997 10.9 1998 10.88 1999 10.95 2000 11.45 2001 11.82 2002 11.87 2003 12.28 2004 12.68 2005 13.25 2006 13.26 2007 13.23 2008 13.2 2009 13.1 2010 12.86 2011 13.92 2012 14.63 2013 15.34 2014 15.54 2015 15.42 2016 15.5