I have self published 8 children's books. Three poetry anthologies and 5 chapter books. They have sold a total of 20,000 copies. The books are selling in and around my own city and in vacation areas that I frequent regularly. Now I would like to submit these books to a publisher. Should I divulge the sale's figures or just keep them to myself.Yes. Let's see, 20,000 divided by 8 is 2,500. Those are certainly good numbers for self-publishing, so you may have a chance.
Don't send all 8 books in a big pile. Choose houses and editors that will be best for single titles, and send that title alone. Specify that title's sales figures. If there's serious interest, then you can mention the other ones.
Consider printing out the manuscripts on plain paper. An obviously self-published work is often a bit of a turn-off for editors, so make your submission look as normal as possible.
Get your manuscripts and cover letters proofread. (The term "sales figures" does not have an apostrophe in it. Putting an apostrophe in a plural is a pet peeve of many editors, and is a bad way to start.)