The world's nine highest-earning sportswomen over the past year are all tennis players.

This is according to research by US business magazine Forbes.

Japan's Naomi Osaka tops the list with earnings of US $37.4 million, ahead of Serena Williams with US $36 million.

World number one Ashleigh Barty is third with an income of US $13.1 million.

United States international footballer Alex Morgan is the only athlete from outside tennis in the top 10, earning US $4.6 million.

[Source: BBC]