Naomi Osaka, a four-time Grand Slam champion who has helped raise awareness of mental health issues in sports, is the world's highest-paid female athlete, according to a list published by business magazine Forbes on Thursday.

Osaka raked in $57.3 million in prize money and endorsements over the last year, nearly all of which came from an endorsement portfolio that added more than 10 brand partners over the last 1½ years.

The list was published after a year in which Osaka withdrew from the French Open to focus on her mental health amid a public row over mandatory press conferences, saying they took too great a toll on her mental health.

Fellow tennis players Serena Williams ($45.9 million) and her older sister Venus ($11.3 million) were next on the list. American gymnast Simone Biles ($10.1 million) and Spanish tennis player Garbine Muguruza ($8.8 million) rounded out the top five.

Tennis players made up five of the list's 10 spots, which Forbes said was the sport's lowest tally in more than a decade and a dramatic change from 2019, when it claimed all 10.

Collectively, the 10 highest-paid female athletes earned a total of $166.6 million, which Forbes said was a 23% increase over its 2020 list.

South Korean golfer Ko Jin-young ($7.5 million), Indian badminton player P.V. Sindhu ($7.2 million), world No. 1 tennis player Ash Barty ($6.9 million), golfer Nelly Korda ($5.9 million) and basketball player Candace Parker ($5.7 million) were the other athletes in the top 10.