Year Cases per 100,000 1990 37.42 1991 103.8 1992 215.2 1993 152.1 1994 131.1 1995 129.9 1996 153.8 1997 128.9 1998 137.4 1999 104.1 2000 47.83 2001 33.95 2002 24.92 2003 17.19 2004 30.31 2005 81.83 2006 66