Relative value charts like this are used to show the changing frequency and locations of bovine spongiform encephalopathy (BSE) cases in North America. By showing different countries in one chart, you can easily compare the total and individual frequencies of BSE.
Text in this example:
1993 2003 2004 2005 2006 2007 Canada 1 1 1 0 1 1 Canada
(born after 1997 feed ban) 0 0 0 1 3 2 Canada
(unk birth date) 0 0 0 0 1 0 U.S. 0 1 1 0 1 0 Bovine Spongiform Encephalopathy (BSE) Case in North America,
by Year and Country of Death, 1993-2007 Year 1993 2003 2004 2005 2006 2007