Following her controversial loss at the U.S. Open last week, Serena Williams has sparked a conversation about equality in tennis.

Williams was fined $17,000 for three code violations in the final match. The chair official first penalized Williams for illegal on-court coaching, which she denied and said she did not see. She then picked up a penalty for smashing her racket, and then a third after calling the official a thief after she believed she was unfairly penalized.

Williams pleaded her case to other officials who were called to the court, and called out what she sees as a double-standard in the sport — saying that male tennis players never face harsh penalties like hers for similar actions.

However, in the four Grand Slam events over the past 20 years, men have been penalized significantly more often than women, according to a New York Times report on Friday.

The report, looking at fines data at Grand Slam events from 1998 to 2018, found that women were fined 535 times, while men were fined 1,517 times.

Women only outnumbered men in two categories over the past two decades — racking up 152 fines for coaching, compared to just 87 for men, and 10 no press fines, compared to just six for men.

Here are some of the biggest fines, from the New York Times:

• Racket Abuse — Men 646, Women 99

• Audible Obscenity — Men 344, 140

• Unsportsmanlike Conduct — Men 287, Women 67

• Verbal Abuse — Men 62, Women 16

• Ball Abuse — Men 49, Women 35

• Visible Obscenity — Men 20, Women 11

The biggest fine in which women were fined for more than men, coaching, is the one that Williams picked up her first penalty for during her loss to Naomi Osaka — which sparked the other two penalties.

More from Yahoo Sports:
• Nike stock closes at all-time high after Kaepernick ad
• Le’Veon Bell congratulates his fill-in RB
• Horrifying allegations against Celtic emerge
• Terez Paylor: Nike’s controversial campaign is nothing new