After three years of modest declines, over the air radio ad revenues are forecast to inch ahead in 2019, according to PwC’s just-issued Global Entertainment and Media Outlook 2018-2022 report. But online audio advertising from traditional radio broadcasters will power the industry’s growth engine over the next five years.

“Terrestrial online advertising revenue will drive the radio advertising landscape over the next five years, as broadcast advertising growth struggles,” PwC says in the new report, released Tuesday evening.

First the over the air numbers: PwC says traditional radio advertising in the U.S. will total $15.90 billion this year, down a smidge from $15.91 million in 2017. The forecast calls for a slight increase to $15.92 billion in 2019, then $15.94 billion in 2020, $15.96 billion in 2021 and $15.99 billion in 2022.

While the 2017-2022 over-the-air trend is for a meager compound annual growth rate of 0.10%, AM/FM radio’s digital streams are on track to grow by an annual rate of 7.8% over the same period. Here’s the streaming trend line for broadcast radio: $1.65 billion (2018), $1.79 billion (2019), $1.93 billion (2020), $2.07 billion (2021) and $2.20 billion (2020).

PwC predicts the oomph of streaming dollars will push total U.S. AM/FM radio revenue up at an annual growth rate of 0.92% from $17.57 billion in 2017 to $18.39 billion in 2022. And it references how ad agency Horizon Media suggested in 2017 that its digital audio inventory could grow exponentially in the next few years.

The U.S. is the largest radio market globally, accounting for nearly half of total radio revenue worldwide in 2017, with total revenues of $22.1 billion for all forms of radio. “Despite other emerging radio sectors experiencing faster growth over the next five years, the U.S. is set to increase its share of global radio revenue, with the market totaling $23.8 billion in 2022,” the report says. Advertising accounted for 81% of total radio revenue in the U.S. in 2017.

The report notes how talk and news stations hit some of their highest audience shares in 2017, accounting for 10.2% of listening by March 2017, according to Nielsen. And with this year’s midterm elections cueing up, the outlook for news/talk remains strong. Radio is also well positioned to seize on the $8.8 billion Borrell Associates projects will be spent during the current election cycle.

The analysts at PwC also point to the impact of programmatic advertising on the radio industry, saying it allows agencies “to more accurately monitor the success of campaigns and target time slots that are most appropriate for their advertising material.” And while online display ads have been the main target of “fraudsters,” the report observes how “audio ads are left relatively unscathed by fraudulent bots and AI [artificial intelligence].”

Looking at Pandora, the report notes that that despite a reduction in listenership numbers, engagement remains high as the webcaster focuses on improving capabilities for advertiser investment to maximize revenues. Meanwhile, iHeartRadio’s streaming platform “has worked hard to integrate into as many spaces as possible,” PwC says, such as on tablets provided in hotel rooms through a partnership with hospitality tech company KEYPR, on smartwatches and other wearables. There’s even an iHeartRadio bot on Facebook Messenger, in response to requests from Facebook users for music recommendations.