Mobile payments of $12.8 billion were made in the US in 2012

"If this week's National Retail Federation "Big Show" in New York didn't demonstrate the growing interest in mobile payments, with its multiple panel discussions and vendor booths dedicated to omnichannel commerce, perhaps a new report from research firm Forrester will add to evidence that mobile payments is, indeed, set to take off. According to Denee Carrington, lead author for the report, U.S. mobile payments will reach $90 billion in 2017 — that's a 48 percent compound annual growth rate from $12.8 billion spent in 2012."
Source:  Mobile payments today, 16th January 2013