Year Cases per 100,000 1990 4.68 1991 4.71 1992 4.72 1993 4.74 1994 4.7 1995 4.73 1996 4.69 1997 4.65 1998 4.58 1999 4.46 2000 4.38 2001 4.28 2002 4.31 2003 4.16 2004 4.04 2005 3.89 2006 3.75 2007 3.64 2008 3.46 2009 3.31 2010 3.16 2011 3.02 2012 2.92 2013 2.86 2014 2.81 2015 2.79 2016 2.79