From The Canadian Jewish News. November 12, 1981:
This ad was run in the fall of 1981. The upcoming season of 1982 would have been the 27th – NOT the 28th.
The 25th Anniversary was celebrated the summer of 1980 – as indicated by this promotional pen:
The summer of 1981 was therefore the 26th. The ad below from 1991 also validates this. It correctly shows that 1991 was the 36th season.