My source is
A Numismatic History of the Birmingham Mint by James O. Sweeny, ISBN 0950759406, page 199.
The Leningrad issue may be less than 86 million, as Sweeny writes "Several mints struck the 1924 5 kopeks".
Just checked the site maintained by our member cam.
There it says:
Leningrad mintage 22.3 million, flat globe, plain edge.
Leningrad mintage 15, flat globe, reeded edge.
Heaton mintage 23.5 million, convex globe, plain edge.
Follow the link above for pictures.
Peter