By 2018, mobile will become the number one format for digital advertising, a new study predicts. Conducted by ZenithOptimedia, the forecast predicts that mobile advertising will more than double in three years, increasing from $50 billion this year to $114 billion. That will account for 50.2% of all internet advertising – more than desktop, which is expected to reach $113 billion in 2018.

According to the study, mobile advertising will grow at an average rate of 32% a year over the next three years, and account for nearly 90% of all new advertising money in the global market. It will become the second largest advertising media format behind television, which will generate $206 billion in revenue in 2015. While television accounts for 38% of total ad spending currently, by 2018 internet will surpass it as the most widely used advertising medium.

Data from Counselor’s State of the Industry study found that 56% of distributors have a mobile-friendly website. While large distributors ($1 million or more in revenue) lead the way with 59%, small distributors ($250,000 or less in revenue) aren’t far behind with 54%.

The Zenith Optimedia study predicts that global ad spending will increase by $6.1 billion next year for a total of 4.7% growth – a figured boosted by the “quadrennial year” phenomenon that includes four-year events like the U.S. presidential election and the Summer Olympics. Global ad spending is on pace to increase by 3.9% this year (a downgrade from ZenithOptimedia’s prediction of 4.3% three months ago) and is expected to keep growing at 4%-5% until at least 2018. The U.S. election alone is expected to contribute $3.2 billion. Ad spending in the U.S. is expected to see more moderate growth compared to the rest of the world, with 3.6% this year and 3.9% next year.