Year Cases per 100,000 1990 157.4 1991 210.4 1992 266.5 1993 310.3 1994 344.1 1995 371.3 1996 385.1 1997 400.3 1998 405.6 1999 419.3 2000 417.9 2001 434.9 2002 437.9 2003 451.8 2004 431 2005 406.7 2006 378.6 2007 351.9