The History of Polio - Image Gallery / CAN-PolioCases -
CAN-PolioCases.jpg
Polio incidence in Canada, 1927-1962, with provincial epidemic peaks
(Christopher J. Rutty, "Do Something! Do Anything! Poliomyelitis in Canada, 1927-1962 (PhD Thesis, University of Toronto, 1995), p. 395)