Why was Jankovic never listed as world number one on Yahoo! Sports?

Question

Records show that Jelena Jankovic was the world number one last week, but she was always listed as #2 and is still indicated as having been #2 last week on the current raknings:

http://sports.yahoo.com/ten/rankings;_ylt=AhyONgLrWy8g5BuhzXOuSTU4v7YF?type=singles&gender=w

Answer 1

She is number two right now.

Answer 2

Hm, yeah, it is a mistake.  She was #1 on August 11th, so it should have said that.