Year Cases per 100,000 1990 0 1991 0 1992 0 1993 0 1994 5.952 1995 15.56 1996 10.92 1997 26.76 1998 37.06 1999 19.87 2000 4.575 2001 2.578 2002 1.705 2003 0.9547 2004 1.553 2005 0.232 2006 0