Oil Companies. How Much Profiting Allowed?

How much profit percentage should oil companies be allowed to make? 1$ profit for every $100 worth of gas or oil sold 2$ profit for every $100 worth of gas or oil sold 4$ profit for every $100 worth of gas or oil sold 8$ profit for every $100 worth of gas or oil sold 10$ profit for every $100 worth of gas or oil sold 15$ profit for every $100 worth of gas or oil sold 20$ profit for every $100 worth of gas or oil sold 30$ profit for every $100 worth of gas or oil sold 40$ profit for every $100 worth of gas or oil sold. 50$ profit for every $100 worth of gas or oil sold Free polls from Pollhost.com

What do you think? Should oil companies be allowed to make whatever profit they can make if people are willing buy their oil based products? What's an "acceptable" profit margin according to you that oil companies ought to be allowed to make?