Year Cases per 100,000 1990 11 1991 17.6 1992 24.9 1993 32.7 1994 39.7 1995 46 1996 50.8 1997 55.7 1998 60.4 1999 65.2 2000 70.4 2001 75.1 2002 79.1 2003 81.2 2004 80.8 2005 78.7 2006 75.8 2007 73.5