Year Cases per 100,000 1990 8.9 1991 12.7 1992 17.1 1993 22.3 1994 28.2 1995 34.6 1996 40.7 1997 47.5 1998 54.5 1999 61.8 2000 69.5 2001 76.8 2002 83.2 2003 87.5 2004 88.7 2005 87.8 2006 85.6 2007 83.3