The group's managing director Jerry Marwood said figures showed that investment had helped to boost performance of both existing and new stores. "We have worked very hard to try to keep stores vibrant, fresh and innovative, as well as offering great promotions and discounts on key products," he said.
Most stores reported a good flow of customers braving the extreme weather for their last-minute purchases.
"In today's tough market, consumers are looking for great value, great brands and great service, and I think that from all the evidence our retailers seem to be supplying just that."
The closure of high street chains such as Threshers had also had a beneficial impact on volumes, he revealed, with alcohol sales up 6%.
While he predicted that tough market conditions would continue, Marwood added: "There is plenty of evidence to suggest that the trends which have driven more customers into our business in 2009 will continue well into 2010."