Digital advertising revenues reached a new high of $31 billion in 2011, up 22 percent year-over-year, according to new data published by the Interactive Advertising Bureau.

The IAB reports the mobile segment experienced the fastest growth of all advertising categories, raking in 2011 revenues of $1.6 billion--an increase of 149 percent compared to 2010 totals. Mobile advertising now accounts for 5.0 percent of all digital advertising revenues, up from 2.5 percent a year ago.

Search remains the leading digital ad format, driving 46.5 percent of total revenues in 2011 to bring in $14.8 billion, up close to 27 percent compared to the previous year. Display-related revenues followed at $11.1 billion, or 35 percent (up 15 percent from $9.6 billion in 2010).

The IAB adds that retail advertisers continue to lead other verticals on Internet ad spending at $7.1 billion, or 22 percent of 2011 revenues. Retailers accounted for 21 percent of revenues in 2010, or $5.5 billion.

The Interactive Advertising Bureau is comprised of more than 500 media and technology companies responsible for selling 86 percent of online advertising in the U.S.