Mobile accounted for 13% of online sales in the US in Q1 2012

"Mobile is capturing a larger share of the online retailer sector in the US, according to a new report from IBM. Mobile commerce grew to 13.3 per cent of all online retail sales during the first quarter.
Mobile devices generated 17.1 per cent of all online sessions on retail sites, making a significant jump from 6.1 per cent in the year-ago period. The iPhone drives 6.5 per cent of mobile device retail traffic while Android captures 5.9 per cent and the iPad comprised 5.3 per cent.
"Over the first quarter, the digitally empowered consumer continued to demonstrate the momentum of the online channel and specifically mobile commerce, which has established itself as a legitimate channel for shopping," says Craig Hayman, general manager at IBM Industry Solutions. "Moving ahead, we will help retailers synchronize the demand and supply chains to address issues of product availability and connect to the mobile buyer.""
Source:  Data from IBM, reported by Mobile Marketing, 3rd May 2012