Year Cases per 100,000 1990 13.3 1991 20.9 1992 31.9 1993 47 1994 66 1995 87.9 1996 110.6 1997 132.3 1998 151.2 1999 166.9 2000 179.5 2001 189.6 2002 198.1 2003 205.1 2004 211 2005 216.5 2006 221.9 2007 227.5