Year Cases per 100,000 1990 5.14 1991 5.1 1992 5.06 1993 5.03 1994 4.99 1995 4.96 1996 4.92 1997 4.89 1998 4.85 1999 4.82 2000 4.79 2001 4.77 2002 4.76 2003 4.75 2004 4.74 2005 4.73 2006 4.69 2007 4.65 2008 4.62 2009 4.59 2010 4.55 2011 4.55 2012 4.56 2013 4.56 2014 4.56 2015 4.57 2016 4.57