Contactless payments account for 20% of transactions at Pret A Manger in the UK

"Contactless payments at sandwich chain Pret A Manger have boomed over the past 12 months, according to the firm's director of IT, delivery and support, Andy Chalklin.
"Contactless payments in terms of our overall transactions have gone from single digits of probably between three to five per cent, to about 20 per cent in the last 12 months," Chalklin told Computing in an exclusive interview.
He said that although the firm moved into the contactless area early on, it is only recently that it has seen a huge surge in users adopting and using the technology.
[...]
He added that the sandwich chain is gaining sales from the use of contactless technology now, and is adamant that the firm will do everything in its power to ensure it is ready for the rollout of other mobile payment solutions.
"I think to be known as a place that accepts contactless cards has raised sales. What I don't want is to fall back; we need to always make sure our devices are the fastest available," he said."

Source:  Computing. 6th March 2013

Note - these are payments through NFC chips in cards, not mobile phones