LONDON: Global advertising expenditure is forecast to grow steadily over the next three years, according to new data from ZenithOptimedia which also highlighted the growing impact of programmatic and mobile.

Figures in the media agency's latest Advertising Expenditure Forecasts report show growth in adspend at 3.9% in 2013 but increasing to 5.5% in 2014, 5.8% in 2015 and 6.1% in 2016.

This year's figures will be helped by a series of 'semi-quadrennial' events – the Winter Olympics, the football World Cup, and the mid-term elections in the US – as well as the eurozone finally turning the corner to achieve its first year of growth since 2010.

While growth in the eurozone is expected to be a modest 0.7%, that will change as more countries stabilise – Finland, Italy and Greece, for example, are behind the curve – and adspend growth will accelerate to 1.6% in 2015 and 1.7% in 2016.

ZenithOptimedia noted that television remained the dominant advertising medium, attracting 40% of spend in 2013, nearly twice that taken by the internet (21%), and would gain most from the semi-quadrennial events, growing 5.2% in 2014.

But the internet was by some distance the fastest-growing medium, up 16.2% in 2013 and forecast to increase at a similar annual rate (16%) for the next three years.

The fastest-growing sub-category was display (21%), which was predicted to overtake paid search (13%) in 2015.

Traditional display (banners and other standard formats) was growing at 16% a year, boosted by the revolution in programmatic buying, which, said ZenthOptimedia, provided agencies and advertisers with more control and better value from their trading. Social media (growing at 29% a year) and online video (23% a year) were also starting to benefit from programmatic buying.

The rapid adoption of smartphones and tablets was driving a boom in mobile advertising, projected to increase at an average of 50% a year between 2013 and 2016. In contrast, desktop internet advertising was slated to grow at an average of just 8% a year.

Over the same period, mobile's share of the market was set to more than double, from 12.9% of internet expenditure and 2.7% of advertising across all media to 28.0% and 7.6% respectively. In doing so it would become bigger than radio, magazine or outdoor, making it the world's fourth-largest medium.

Data sourced from ZenithOptimedia; additional content by Warc staff