Mobile ad spend in the US in 2014 rose 76 per cent from the previous year, to a total $12.5bn (£8.3bn), according to the annual report from the IAB and PwC.

This means that mobile now accounts for a full quarter of US digital ad revenues, which hit a record $49.5bn – a year-on-year increase of 16 per cent, making 2014 the fifth consecutive year of double-digit growth for the industry.

“High double-digit growth in mobile advertising is a reflection of the continued shift in consumer behavior away from desktop and towards mobile devices,” said David Silverman, Partner, PwC US. “A prominent rise in social, a significant mobile activity, is driving growth in advertising revenue as consumers spend more time connected.”

Elsewhere, search took the biggest share of spend, at 43 per cent ($3.3bn, up 17 per cent), followed by display at 30 per cent ($13.5bn, up five per cent).

When it comes to pricing models, performance-based ads still rule the roost, accounting for $32.4bn of spend, to impression-based ads $16.5bn.