Where to find sales no. for proposal

There's no public source for this info. If you were in the business, you could get the numbers (more or less) from a service called Bookscan, but it's not free.

MTF

That's not quite true. You can get SOME of the numbers sold through the Ingram's stock automated phone, and also Baker & Taylor's similar phone number. Ingrams and B&T are two of the larger wholesalers/distributors in the United States. (In other words, they buy in bulk from the publisher and then re-sell to bookstore chains and independents that are under contract with them.)


The Ingram's Automated Stock Information phone number is:
(615)213-6803 (toll call)
or
(800)937-8000, choose option 4, and enter extension #36803

Follow the directions given. You'll need your ISBN before you call, and you'll get the most information if you enter option 3. This will tell you how many are in stock across all of the Ingrams warehouses, which warehouses stock the book, sales this week, sales this year, and sales the previous year.

The Baker & Taylor Stock Information phone number is:
(800)233-8467 (toll free)

Again, you'll need your ISBN and they'll provide the warehouses, the number stocked and the number sold.

Hope that helps!

Given that the Ingram and B&T numbers aren't anywhere near the whole market for a book's sales (chains usually order direct from medium and big publishers), I don't see how they would help.

Anyway, I wouldn't try to put this level of detail in a book proposal. (Definitely not in a novel query.) Publishers don't expect or need numbers from you. They will make those calculations themselves if they're interested enough.

MTF