Corporate chains aren't my forte.
@volfanhill can give you a better guess than I can.
I've worked for 6 mom and pop restaurants on an administrative level at this point. The best I've seen in a year is about 17%. The worst (but still profitable) was about 2%. There are other factors to consider like the commercial space market in any given city and, most importantly,
whether it's a restaurant or a bar. I've seen bars eclipse 20% before. Typically, the more spirit/cocktail oriented it is, the more money it prints. Wine and beer are nowhere near it.