Year Cases per 100,000 1990 3.81 1991 3.88 1992 3.95 1993 4.01 1994 4.08 1995 4.16 1996 4.24 1997 4.32 1998 4.41 1999 4.5 2000 4.59 2001 4.61 2002 4.63 2003 4.65 2004 4.68 2005 4.7 2006 4.74 2007 4.79 2008 4.83 2009 4.88 2010 4.93 2011 4.95 2012 4.98 2013 5.01 2014 5.03 2015 5.06 2016 5.09