Over the past year, Facebook Messenger, Instagram, WhatsApp did not grow fast enough to offset Facebook’s sagging flagship service.

That’s according to Pivotal Research, which analyzed data on domestic digital content consumption from Nielsen.

From June 2017 to June 2018, Facebook’s family of sites saw its share of digital consumption drop two percentage points — from 17.2% to 15.2% — Pivotal points out. 

Dragging down aggregated time spent for all content measured, Facebook’s core property and Messenger declined by 10%, year-over-year. Even including Instagram and WhatsApp, the metric declined by 6%.

Usage was negatively impacted by a mere 1% increase growth in users on the core platform, during the period.

Instagram experienced a 13% increase in growth. Yet, because the unit is still just 13% of Facebook’s size (measured by time spent on the platform by all of its users), its impact remains limited.

Beyond Facebook’s mature status, it’s difficult to diagnose the company’s troubles, says Pivotal analyst Brian Wieser.

“It is impossible to identify whether or not Cambridge Analytica and concerns around data privacy had any impact here, nor if Facebook’s efforts to improve the quality of time spent (at the expense of volume of time) might be having a desired effect,” Wiener concedes in the report.

“To the extent that Facebook continues to hold a share of consumption at around 15%, it implies Facebook is over-monetizing (versus) the industry to a significant degree,” Wiener warns.

For the year, Pivotal’s forecast for Facebook’s share of domestic digital ad revenue is around 23%.

Google, by contrast, appears to be having a great year.

From June 2017 to June 2018, Google’s YouTube, Google and Waze saw its share of digital consumption increase from 28.6% to 34.2%.

This metric includes time spent with content tagged with any Google URL, including AMP-delivered content for other publishers’ properties, Pivotal notes.

“While Google does not directly monetize all (or even most) of the growth associated with AMP, it is still important to Google, as it reflects the degree to which they are capturing data and enhancing the importance of their various ad tech and marketing tech tools,” according to Wieser.