Zenith, a forecaster owned by the ad agency Publicis Groupe SA, said it expects spending to grow by 4.2 percent in 2011, down from a 4.6 percent forecast issued in December.

Zenith notes that TV advertising disappeared in Egypt during the revolution there, and Japanese broadcasters replaced most spots with public-service announcements for weeks after the earthquake.

Much of the growth is coming from developing markets like China.

For the US, Zenith projects a 2.5 percent increase in advertising.