Year Cases per 100,000 1990 22 1991 26.3 1992 34.8 1993 44.7 1994 56.4 1995 67.7 1996 79.4 1997 93.2 1998 105.5 1999 115.4 2000 119.9 2001 117.7 2002 117.3 2003 118 2004 115.1 2005 102.3 2006 90.8 2007 84.4