NEW YORK (Reuters) - Meta said on Friday its flagship app Facebook is attracting its highest number of young adults in three years, as it tries to shake the platform's reputation as a hangout for an older generation.

The social media network said that more than 40 million U.S. and Canadian adults aged 18 to 29 now check Facebook daily, in Meta's first-ever release of such demographic information. Facebook, whose founder Mark Zuckerberg turned 40 last month, marked its 20th anniversary this year.

The growth reflects the company's efforts to recapture the attention of young adults who have been flocking to short video app TikTok, owned by China's ByteDance.

Meta charted "five quarters of healthy app usage growth" among young adults, a company spokesperson said.

Facebook, founded in a Harvard University dorm in 2004, spread like wildfire across U.S. college campuses and became the default mass communications platform for a generation of users. The app amassed 50 million users within its first three years and now has 3.2 billion users globally.

Along the way, however, it became less attractive to young users who drive consumer fads and are considered crucial by the advertisers responsible for most of Meta's ad sales.

Only about a third of U.S. teens say they use Facebook, according to a survey last year by research organization Pew, a sharp drop compared to previous surveys the group conducted in 2014 and 2015.

By comparison, the share of all U.S. adults who say they use Facebook has remained relatively flat since 2016 at around 68%, Pew has said.