US total media ad spending in 2013 will be grow 3.8 percent to $171.33 billion, an increase of more than $6 billion from 2012, according to a new eMarketer report.

The report predicts a slight increase in spending in 2014 as well, with marketers allocating more dollars toward the FIFA World Cup soccer tournament, the Winter Olympics and midterm elections.

Mobile ad investments will continue to fuel growth, it said.