According to a recent report from Adobe, search is still “the biggest driver of return on investment,” in regards to advertising. The quarterly report, entitled “Adobe Digital Index: Global Digital Advertising Update,” stated that compared to Q1 in 2011, search expenditures increased 16 percent in the U.S. and 3 percent in the United Kingdom.

An increase in clicks is driving the growth, and not higher prices advertisers are forking over for these clicks, which reportedly fell 5 percent for Google. It should be noted that the above graph might also suggest that search spending was down from Q4, 2011, though this might be plainly a seasonal variation.

While traditional search advertising is steadily growing, newer areas like mobile and social are expanding at a faster pace. Accelerated by tablet adoption, mobile traffic overall is up 4-fold. At present, mobile makes up 8 percent of U.S. search spending, and 11 percent in the UK – that’s 250 percent growth in the UK from this time last year. Facebook spending is up 93 percent, and general engagement rose 176 percent.

The Adobe report prognosticates that ad search spending in the U.S. will grow 10 to 15 percent over the course of the year, and that tablet and mobile spending will comprise 15 to 20 percent by the end of the year. Digital marketing company Efficient Frontier, recently acquired by Adobe, conducted the study, though the actual report is not yet online.