Year Cases per 100,000 1990 4.7 1991 6.6 1992 7.7 1993 8.2 1994 8.6 1995 8.8 1996 9.1 1997 9.4 1998 9.7 1999 10.1 2000 10.5 2001 10.9 2002 11.3 2003 11.7 2004 12 2005 12.3 2006 12.6 2007 12.9