Shares in pizza delivery firm Domino's Pizza fell over 8% after it said like-for-like sales for the first seven weeks rose 4.7%, down from an 11.9% increase for the 52 weeks ended 26 December 2010."This figure comes against the backdrop of exceptional comparatives from the same period in 2010 and the current difficult economic climate," said chief executive officer Chris Moore.The group posted a 27.3% rise in full year pre-tax profit to £38m, helped by booming online sales. Sales increased by 19.3% to £485.3m during the year.Domino's said it is confident of delivering another year of strong progress. Online sales for the first seven weeks were up by 72.9% against the same period last year. "With an app for the iPad and an app for android mobiles due imminently, we are confident of seeing even more business come through these channels," Moore said.Looking ahead Moore added, "I am confident that we will deliver another year of strong growth."The total dividend has been increased by 31.6% to 10.20p.