Two days after the statement date, like clockwork. My most recent statement date was Aug 10th, and this morning they were in my account.
Edited to add. The two day or 24 hr discussion is a technicallity.... My experience is that the statement won't actually run until Aug 10th late at night (around 11pm CST). That being said, the miles will post very early in the morning on the 12th, So 24-30 hours is the norm for me...
For most people that don't pay that much attention, just expect the miles two days after your statement day... Or continue to refresh your citi page until you see the statement, and then expect them 24 hours from that... All in all, it makes little difference.