Compared to a year ago, time spent on the social network has fallen by almost 7%, according to an analysis of new Nielsen data.

The amount of time people are spending on the Silicon Valley company's main social network has dropped by almost 7% from a year ago, according to new data from research firm Nielsen that was highlighted in a recent research note by Pivotal's Brian Wieser.

"Overall, including Facebook, Messenger, Instagram and WhatsApp, Facebook's share of digital consumption was at 15.2% vs. 16.9% in the year-ago period," Wieser wrote in his note.

Facebook will have around a 23% share of US digital ad revenue this year, he said, noting that percentage is significantly higher than its share of users' time.

A new study of teens by Common Sense Media cited by Axios found that only 15% of those aged 13 to 17 said their "go-to social site" was Facebook.

In 2012, it was the go-to site for 68% of that age group.