Year Cases per 100,000 1990 28.28 1991 28.38 1992 28.66 1993 28.83 1994 29.07 1995 29.24 1996 29.31 1997 29.31 1998 29.18 1999 29.11 2000 28.85 2001 28.41 2002 27.97 2003 27.68 2004 27.32 2005 26.81 2006 26.1 2007 25.5 2008 24.83 2009 24.15 2010 23.55 2011 23.06 2012 22.58 2013 22.34 2014 22.06 2015 21.91 2016 21.74