Percentage of tour singles titles that are Grand Slam titles

Naomi Osaka 50% (3 of 6)
Serena Williams 31.5% (23 of 73)

For comparison:

Martina Navratilova 10.8% (18 of 167)
Chris Evert 11.5 % (18 of 157) pic.twitter.com/LBitoLc6he

— Christopher Clarey (@christophclarey) February 18, 2021