History
The London Daily Telegraph, which had been ranking male players since 1914, began ranking women players, as well, in 1925.
Only amateur players were eligible for ranking until 1968, when the major tournaments were opened to professionals.
In 1973, the Women's Tennis Association developed its own rating system. Now done by computer, the ratings are updated weekly and are used for tournament seedings.
The listing here shows the player ranked first in the world by the WTA system at the end of the year.