I will agree with everything Mark has asked for, but I would also like to see a break down by sector of business. Residential, Commercial, Industrial, estimated percentage of each if they do multiple. Average size of work done. Small jobs, couple weeks, couple months, you get it.
I'm not sure how easy it would be to include, but I wouldn't mind knowing how much work they do. By that I mean, do they just mount equipment/program and test. Or just program and test, or just pulling the cable, or all of the above. Or a mix? I've done jobs where I go from beginning to end on my own, and others where I have a contractor pull my cable and mount my devices.
This is a weird one, probably not important but something I've always wondered. Do they work in pairs or by themselves? In my 5 years of experience it seems like companies are trying everything they can to get people to do everything alone. Always bugged me. Doesn't make sense to have two guys on every job, but a lot of the time it makes sense in my mind to have two people (or more, depending on the size of the project I suppose)