SAN FRANCISCO, Jan. 16 (Xinhua) -- Most Facebook users are not aware that their traits and interests are being tracked and recorded by the company without their prior knowledge, a new study suggested Wednesday.

"Seventy-four percent of Facebook users say they did not know that this list of their traits and interests existed until they were directed to their page as part of this study," said the Pew Research Center, a nonpartisan American fact tank based in Washington, D.C.

About 51 percent of those surveyed are not comfortable with Facebook compiling this information, while 27 percent agree the listings do not accurately represent them, it added.

Pew surveyed nearly 1,000 U.S. Facebook users aged 18 or older in a nationwide poll conducted between September and October in 2018.

Pew said most commercial sites, from social media platforms and news outlets to online retailers, gather a wide variety of data about their users' behaviors such as their browsing habits or interests to allow advertisers to target precisely a certain group of Internet users with classified advertisements.

A large majority of Facebook users, about 88 percent, found the world's biggest social media site had generated some material for them on the ad preferences page, with about 59 percent saying the collected information "reflects their real-life interests," Pew said.

The study noted that 84 percent of social media users said it is easy for those commercial sites to identify their race or ethnicity, while 79 percent said their hobbies and interests were easily grabbed on the sites.

Although Facebook has promised to give its users "complete control" over their information as its chief executive officer Mark Zuckerberg told lawmakers in a hearing in Congress last year, the Pew study revealed that most users of the Northern California-based tech powerhouse did not have enough knowledge about Facebook's tactics or algorithms to collect their personal data on the platform.

Facebook is the third most trafficked website in the world and fourth most in the United States. It had 2.27 billion monthly active users, Zuckerberg disclosed in October.

Pew said the company's global user base is bigger than the population of many countries, and that is one of the reasons why it chose Facebook to study public attitudes about digital tracking systems and algorithms.