Year Cases per 100,000 1990 34.7 1991 51.2 1992 69.1 1993 88.9 1994 108.7 1995 128 1996 144.5 1997 162.3 1998 180.3 1999 199.2 2000 219.6 2001 238.9 2002 255.8 2003 266.8 2004 268.9 2005 264.9 2006 257.4 2007 250.2