Since going public in 2006, shares of restaurant company Chipotle Mexican Grill (NYSE: CMG) are up over 3,800%, making it one of the greatest restaurant stocks of all time. Since going public, Chipotle has opened many more restaurant locations, sales per location have soared, and profitability has consequently skyrocketed. Investors shouldn't overlook Chipotle's annual sales per location, otherwise known as its "average unit volumes."