Lucas Shaw:

Television-advertising sales in the U.S. fell 7.8 percent to $61.8 billion last year, the steepest drop outside of a recession in at least 20 years, while sales at cable networks slumped for the first time in almost a decade. And there’s no sign of a pickup in 2018, excluding cyclical events like the Olympics and the midterm elections, according to data from Magna Global.

The decline in TV viewership is accelerating as online rivals Google and Facebook have increased their investments in video, capturing almost every new advertising dollar entering the marketplace. Television ad sales have fallen even as global advertising grows, leading research firms and analysts to predict that the business may never recover.