That's toughie. Is a success counted when the first company does well, or if the entrepreneur goes on to make a ton of amazing companies, giving some stock to the accelerator and/or having them involved in the process?
Compiling further detailed information on the programs would certainly be interesting and I'm sure that prospective applicants would find it helpful. Given the different models used by the programs, it would be an interesting endeavor to try to consolidate and compare the details.