Year Cases per 100,000 1990 9.8 1991 13.4 1992 17.4 1993 22 1994 27.2 1995 32.8 1996 38.2 1997 44.4 1998 50.9 1999 57.6 2000 64.7 2001 71.2 2002 76.8 2003 80.2 2004 80.8 2005 79.2 2006 76.5 2007 73.6