Pizza Hut is the largest pizza purveyor in the world, with 12,583 total restaurants and combination delivery/takeout units in 90 countries; 6,590 units are company-owned.
Domino's Pizza is the world leader in delivery, with 5,500 stores in 46 international markets.
Papa John's is considered the fastest growing franchise in the USA, with 1,160 units generating £383 million in sales in 1996. (source: "Chain Store Guide".)
Of 31,386 pizza franchise units in the United States, roughly 83 percent (24,381 stores) offer delivery, 91% offer takeout, and 51% offer dine-in service.