Year Cases per 100,000 1990 26.74 1991 26.81 1992 26.89 1993 26.98 1994 27.07 1995 27.18 1996 26.76 1997 26.36 1998 25.98 1999 25.6 2000 25.25 2001 24.6 2002 23.98 2003 23.39 2004 22.81 2005 22.26 2006 21.99 2007 21.7 2008 21.44 2009 21.18 2010 20.93 2011 20.78 2012 20.65 2013 20.51 2014 20.38 2015 20.25 2016 20.13