Year Cases per 100,000 1990 21.63 1991 22.83 1992 24.08 1993 24.67 1994 25.56 1995 26.82 1996 28.22 1997 30.03 1998 29.75 1999 29.29 2000 28.51 2001 27.86 2002 27.84 2003 26.56 2004 26.01 2005 25.49 2006 25.24 2007 25.2 2008 24.73 2009 24.67 2010 24.16 2011 23.64 2012 23.64 2013 23.48 2014 23.28 2015 23.08 2016 22.87