Transfer bonuses

Has there been any apparent consistency to the offering of 50/100% transfer bonuses? I have some miles that I'm anxious to transfer, but not in a major rush. I know that nobody here has a crystal ball, but I was hoping for some insight. I've looked up the dates of the last offerings, but I haven't seen a pattern. Although I haven't run a regression on Delta's stock prices...

Any insight would be appreciated.

Thanks again.