HBO and Showtime don't release them the majority of times. If they have an overachieving PPV, such as De La Hoya and Mayweather they do, probably to brag about it. They don't release every one though. Your best bet are websites like ESPN which sometimes release the information directly from insiders.
Google them - if you get no results, it means the PPV numbers for the fight weren't released, and were below average.
These are publicly held company's and they must devuldge these numbers at their annual shareholders meetings.Purchase one stock share and you will have it sent via Fed ex to your doorstep.:good