Year Cases per 100,000 1990 5.89 1991 5.68 1992 5.51 1993 5.35 1994 5.27 1995 5.32 1996 5.42 1997 5.61 1998 5.93 1999 6.16 2000 6.43 2001 6.52 2002 6.56 2003 6.45 2004 6.15 2005 5.67 2006 5.27 2007 4.97 2008 4.7 2009 4.38 2010 4.17 2011 4.02 2012 4.05 2013 3.95 2014 3.93 2015 3.93 2016 3.96