Hey Thor, It all depends on a bunch of variables. Blades sharp, Ice thickness and hardness, how fast you try to drill ect.
I always bring a quart of extra with me just in case someone lays it down wrong with the vent cap open. It is also a good standby if you ever need to get a quick fire going to get warmed up.
One thing I will caution us all on is the fumes of gas on your hands when you put your baitfish on the hook. I try real hard to avoid touching any gas stuff prior to baiting my hooks, lanterns, augers and heaters all leave a stink that could be transfered to the bait. Never use a JONI type handwarmer in your pocket that runs on lighter fuel. You will spend the day wondering why nothing touches your stinky bait. Been there, done it and learned that lesson.