SAN FRANCISCO, United States — Facebook Inc.'s Instagram is most popular for people younger than 25, who the company says spend an average of more than 32 minutes a day on the photo-sharing app.

For those 25 and older, usage is more than 24 minutes a day, the company said. Instagram is crediting much of the growth in engagement to its “Stories,” which was launched a year ago as a copycat to Snapchat’s feature with the same name. The function allows people to upload short videos of their day that disappear after 24 hours and Instagram’s version now has 250 million daily users.

The new statistics may be salt in the wound for Snapchat, which last reported 166 million users for its overall app, although it may outpace Instagram in terms of time spent. Snapchat users spent over 30 minutes per day on the app in the first quarter, according to newly-public parent company Snap Inc.

Time spent is an important metric for advertisers, which like to hear that users are browsing an app beyond quick checks for updates, making them more likely to run into some marketing. Instagram last disclosed the number almost three years ago, in October 2014, when it announced people were spending 21 minutes per day overall.

By Sarah Frier; editors: Jillian Ward, Robert Fenner, Edwin Chan.