Year Cases per 100,000 1990 6.81 1991 6.71 1992 6.63 1993 6.55 1994 6.47 1995 6.39 1996 6.3 1997 6.22 1998 6.14 1999 6.06 2000 5.98 2001 5.94 2002 5.91 2003 5.88 2004 5.84 2005 5.81 2006 5.83 2007 5.84 2008 5.86 2009 5.87 2010 5.9 2011 5.9 2012 5.9 2013 5.91 2014 5.91 2015 5.92 2016 5.93