Cheese prices remain steady.
Cost of natural gas jumps as temperatures drop.
Some chains donating specialty pie sales to charities related to American Heart Month.
Data also measured customer loyalty in QSR, casual dining categories.
Natural gas prices dropped 9 percent in 2011.
The big chains predict sales of 1 million to 2 million pizzas on Feb. 5.
Pizza stocks not affected by stock market dip.
Yum! Brands, Papa John's stocks are hot.
Yum! Brands reaches another 52-week high.
Stocks were hot as companies focused on domestic and international growth.
Gas prices stabilize after months of falling.
Cost of natural gas also down nearly 40 cents.
100 million Americans expected to patronize a restaurant for the holiday.
Stocks continue to rise on European debt deal.
Cheese, wheat and gas prices continue to slide.
Cheese, wheat prices fall.
Domino's Pizza turns in another 52-week high.
Pizza Inn, Papa John's hit new 52-week highs.
Papa John's stock surges after strong earnings report.
Boosting the quarter's performance was a heavier focus on national media, as well as the execution of a premium price point plan.