Year Cases per 100,000 1990 2.32 1991 2.31 1992 2.3 1993 2.29 1994 2.28 1995 2.27 1996 2.36 1997 2.46 1998 2.55 1999 2.66 2000 2.77 2001 2.93 2002 3.1 2003 3.28 2004 3.48 2005 3.68 2006 3.83 2007 3.99 2008 4.15 2009 4.32 2010 4.5 2011 4.48 2012 4.46 2013 4.44 2014 4.42 2015 4.4 2016 4.39