Year Cases per 100,000 1990 26.5 1991 25.96 1992 25.45 1993 24.81 1994 24.45 1995 24.18 1996 23.81 1997 22.89 1998 22.42 1999 21.93 2000 21.5 2001 21.16 2002 21.14 2003 20.95 2004 20.69 2005 20.25 2006 19.89 2007 19.78 2008 19.42 2009 19.02 2010 18.62 2011 18.27 2012 18.13 2013 17.97 2014 17.73 2015 17.62 2016 17.52