The above graph, adapted from Statistics Canada S232-245, applies to apartment of six units or more. I’ve noted before that the early 1960s saw unprecedented build-out in apartments in Ottawa and competition was fierce. We’re by-and-large used to rates nowadays being somewhere between 0.5 and 2.5%, but at its peak in the Ottawa-Hull CMA, it had reached 9.1%. I will be doing more with this sort of information later but figured it would be nice to share.
I should note that in the series, 1974 has measures for both June (3.6%) and December (2.8%).