Year Cases per 100,000 1990 47.03 1991 45.07 1992 43.16 1993 41.04 1994 39.41 1995 38.42 1996 38.09 1997 37.78 1998 37.36 1999 34.76 2000 33.44 2001 33.39 2002 33.08 2003 32.05 2004 31.66 2005 30.95 2006 29.86 2007 28.69 2008 27.37 2009 26.09 2010 25.01 2011 24.15 2012 23.5 2013 23.03 2014 22.89 2015 22.87 2016 22.79