It began in 1968 when the Grand Slam tournaments allowed professional players to compete with amateurs, ending the division that had persisted in men's tennis since the dawn of the sport in the 19th century.
[2] All records are based on data from the Women's Tennis Association (WTA), the International Tennis Federation (ITF), and the official sites of the four Grand Slam tournaments.
Court claimed both US National titles played in 1968 & 1969 alongside the US Open, but these tournaments were subsequently downgraded to non-Grand Slam status.
These weekly rankings determine tournament eligibility and seedings.
As prize money has increased strongly in recent decades, the lists of prize money leaders for the Open Era (since 1968) and for the WTA Tour period (since 1973) are the same.