Miles per tank & MPG on 99 Malibu

I just purchased a 99 Malibu with a 3100V6 Vin J to save some money on fuel. How many gallons does the fuel tank hold? I've figured out the car gets 24mpg in town and 29mpg straight highway, but i haven't gotten the fuel low yet.

I think the tank holds 15 gallons. When I ran out of gas (only time ever in my life...) it took 13.5 or so.