Bank of Canada printers issue 10,000,000 notes per 2 letter prefix. Hundreds of 2 letter prefixes (like your TN note) were issued so the catalogues do NOT LIST EACH prefix. CHARLTON catalogues create tables before each series so you can go to your library, borrow one from the REF section, if you’d like to see your prefix listed on the table. If your prefix is not mentioned in the Book Value section then that means you have a regular prefix & the premium is minor (depending on the note’s condition). Coinsandcanada also generated tables for the book value of prefix ranges (the first line) & then identify the important (tough) prefixes for the 1969-1979 Series.
Once they used up the 2 letter prefixes they generated 3 letter prefixes. This means that nearly a billion of these notes were printed & it is one of the important lessons collectors need to wrap their head around when saving any particular note (signature, serial # + prefix & condition are paramount) for their collection. A banknote is a package deal (there’s a lot of info packed into each note). It is sometimes difficult for me to peruse the social media platforms which recommend others to certify common notes (even from older series) if the note doesn’t have something particularly uncommon about it. Condition rarity is another “can of worms” that some collectors chase but won’t get into here.
I hope this makes sense to you.
