Forbes released their annual World’s Highest-Paid Athletes list last week. This year was the first year in eight years that the list of 100 athletes did not feature a single woman.

According to Forbes, their list includes all prize money, salaries, endorsements and bonuses earned between June 1, 2017 and June 1, 2018.

Floyd Mayweather tops the list, with an estimated annual earning of $285 million. The rest of the list is largely full of NBA players, football players, baseball players and soccer players.

Last year, the only woman on the list was Serena Williams, who came in at No. 51, earning an estimated $27 million. Forbes says she likely fell off the list due to her 13-month maternity leave. She gave birth to her daughter, Olympia, in September.

Even though Williams earned $18 million in sponsorship deals this year, she was still $5 million shy of the lowest-paid athlete on the top 100.

“The reason why she’s dropped off the list is what we call the motherhood penalty,” Khetsiwe Dlamini, UN Women’s chief of staff, says

It seems striking that Serena Williams only earned about 6 percent of the No. 1 athlete’s earnings. And after Williams, earnings for women athletes only go down more.

“There is a huge drop-off after the 23-time Grand Slam champ when it comes to current earnings among female athletes.” Kurt Badenhausen of Forbes wrote.

So while it’s likely that Serena Williams will return to the list again next year, why is she the only one that seems to be a real possibility?

According to Badenhausen, team sports make up 82 percent of this year’s list. “Salaries in team sports have exploded over the past 25 years as media companies have spent billions on TV deals for live sports content.” Badenhausen wrote.

Equal pay in women’s team sports was a big issue this past year. In 2017, many women’s sports teams initiated campaigns advocating for gender pay equity, with the U.S. Women’s National Soccer Team winning higher pay and the U.S. Women’s National Hockey Team reaching an agreement to end a wage dispute. And, according to a 2017 BBC global sports study, a total of of 83 percent of sports now reward men and women equally.

While that’s some progress, it’s still not enough for the men and women’s soccer players to earn the same amount, Badenhausen says.

“The U.S. national women’s soccer team getting better pay is great, but it is still not taking them to a $20 million salary that is going to put them on the top 100,” he says.

So what would put women athletes in the top 100?

Larger viewership, Badenhausen says.

For example, “the WNBA’s TV contract is $25 million a year because it doesn’t have the viewership to support more revenue and ad revenue to pay for a higher rights fee. The NBA’s rights fee is 100 times that annually.”

Greater viewership also leads to higher visibility, which in turn can also lead to greater endorsement deals for sponsors.

Nancy Hogshead-Makar, former U.S. olympic swimmer and founder of Champion Women, an organization that advocates for equality and accountability in sport, says she rejects this notion that it is a function of the market.

Hogshead-Makar cited the Tucker Center for Research of Women and Girl’s in Sports’ campaign #HeresProof, which works to dispel what they consider to be the myth that people are not interested in and do not watch women’s sports, using infographics to cite statistics of increased women’s sports viewership. For example, one infographic highlights that the 2015 Women’s World Cup Match was the most-viewed U.S. soccer match ever.

Yet, it’s hard to ignore that generally speaking, women’s sports do have less viewers than men’s sports. While the 2015 Women’s World Cup Match had high viewership and Serena Williams’s matches have high viewership, these tend to be exceptions when it comes to women’s sports viewership.

Lower viewership could be due to a number of reasons beyond interest. Women’s sports are often harder to find on TV. According to a 25-year study of gender in televised sports news and highlight shows, researchers found that in 2014, only 3.2 percent of local network affiliates and ESPN SportsCenter coverage went to women, down from 5 percent in 1989.

It is seemingly a chicken-and-egg problem. Without more viewers, networks won’t enter multi-billion dollar deals to cover women’s sports. Yet, without more coverage and promotion of women’s sports, how will the viewers come?

Hogshead-Makar argues that it all comes down to gender-based stereotypes. People, including media executives, still view sports as a men’s game, and their decisions reflect that, she argues.

“Until we break this juggernaut of sports equals masculinity ... we’re going to continue seeing results like this year’s top 100 list.”

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