Year Cases per 100,000 1990 8.8 1991 10.6 1992 12.4 1993 13.8 1994 15 1995 15.7 1996 16.1 1997 16.1 1998 15.9 1999 15.5 2000 14.9 2001 14.3 2002 13.6 2003 12.9 2004 12.2 2005 11.6 2006 11 2007 10.5