The gulf between usage on G+ and Facebook has always been large, but comScore's numbers show a downward trend for Google's fledgling social network. Users spent 4.8 minutes on the network in December and 5.1 minutes in November, the report said.
The usage figures come after Google has trotted out some impressive stats outlining Google+'s growth. In a call with analysts last month, Google CEO Larry Page said Google+ had 90 million users compared to 40 million in October.
Reps from Google could not be reached for comment on the report. In the past, Google has taken issue with third-party reports about Google+, noting that they don't track users who access the site remotely, among other factors. (ComScore doesn't include mobile users in its data, though it plans to soon.)
Google is putting a huge amount of emphasis on Google+. Last April, Page
Despite the latest report, though, there's some encouraging news for Google: Website-Monitoring crunched the numbers this month and found that Google+ is getting less male dominated and is catching on big in India, where 13.69% of Plussers now originate.