NEW YORK (REUTERS) - Digital advertising revenue in the United States increased 15 per cent to a record US$36.6 billion (S$45.2 billion), according to the organisation that tracks digital spending.

Advertisers turned mostly to search ads, the format that dominated almost half of total spending representing 46.3 per cent at US$16.9 billion.

The latest report released on Tuesday is from the Internet Advertising Bureau, which counts as members more than 500 media and technology companies responsible for 86 per cent of online advertising in the US, and consulting firm PricewaterhouseCoopers.

Mobile advertising - a form of revenue many companies from Facebook to Yahoo to Google are trying to increase as more people use smartphones and tablets - represented 9.2 per cent of the total US digital ad revenue at US$3.4 billion.

Display advertising, including video, rose 33 per cent to US$12 billion and represented almost 33 per cent of total revenue.