Conversation so far:
What was Marissa Mayer's relationship with Google?
She joined Google in 1999 as employee number 20.
What was her position/title?
She started out writing code and overseeing small teams of engineers.
Did she have success in this job?
She became known for her attention to detail, which helped land her a promotion.
What did she get promoted to?
promotion to product manager, and later she became director of consumer web products.
What year did she get promoted?
CANNOTANSWER.
How long did she work for Google?
CANNOTANSWER.
Any other interesting information?
Mayer started the Associate Product Manager (APM) program.
What did that program entail?
a Google mentorship initiative to recruit new talents and cultivate them for leadership roles.

Question: When did she start this?
Self-contained rewrite: When did Marissa Mayer start the APM program?