Year Cases per 100,000 1990 9.7 1991 9.55 1992 9.4 1993 9.25 1994 9.11 1995 8.98 1996 8.45 1997 7.97 1998 7.51 1999 7.08 2000 6.68 2001 6.39 2002 6.12 2003 5.86 2004 5.62 2005 5.38 2006 5.29 2007 5.19 2008 5.1 2009 5.01 2010 4.92 2011 4.95 2012 4.99 2013 5.02 2014 5.06 2015 5.09 2016 5.13