The database does not include the ages of the predictors, unfortunately, but the results seem to contradict the Maes-Garreau law. Estimating that most predictors were likely not in their fifties and sixties, it seems that the majority predicted AI would likely happen some time before their expected demise.

Actually, this was a miscommunication - the database does include them, but they were in a file Stuart wasn't looking at. Here's the analysis.

Of the predictions that could be construed to be giving timelines for the creation of human-level AI, 65 predictions either had ages on record, or were late enough that the predictor would obviously be dead by then. I assumed (via gwern's suggestion) everyone's life expectency to be 80 and then simply checked whether the predicted date would be before their expected date of death. This was true for 31 of the predictions and false for 34 of them.

Those 66 predictions included several cases where somebody had made multiple predictions over their lifetime, so I also made a comparison where I only picked the earliest prediction of everyone who had made one. This brought the number of predictions down to 46, out of which 19 had AI showing up during the predictor's lifetime and 27 were not.