A report from Zenith shows that this was followed by the pharmaceuticals and healthcare industries, then alcohol sector, respectively.
At the bottom of the table was telecommunications, followed by food and drink.
The clients also agreed that data has "significantly improved" their understanding of customers but this has "not yet transformed their buying efficiency or brand growth".
Vittorio Bonori, Zenith’s global brand president, said: "Brands have the opportunity to harness data and technology to transform their businesses and accelerate brand growth, but are having difficulty in turning theory into practice.
"Agencies must step up and work in partnership with their clients to unlock the true potential of this revolution in communications."