Smartphones and tablets accounted for almost a fifth (18%) of total US search spend in Q4 2012, according to data from IgnitionOne.
Year-on-year figures show that paid search spend on tablets has increased by 163% compared to 87% on smartphones, while clicks have increased by 135% and 29% respectively.
The report also found that CPCs have increased by 45% on smartphones, while tablet CPCs have increased by a relatively low 12%. On tablets search ad impressions increased 212% while on smartphones the increase was 20%.
Separate figures published by the IAB in October show that mobile advertising accounts for 7% of all digital ad spend in the UK. So though the reports focus on different markets, it still suggests that mobile search is outperforming other areas of mobile marketing.