I would have expected a higher percentage. Few openings and a high bar for whatever there is. It was tough to get an assistant professor job 30 years ago and I can't imagine what it must be like now.
Ditto, I would have thought it would be somewhere in the mid to high nineties.
Keep in mind that this is a postdoc. The thing you do after you complete a PhD, and for most of history, something you only did after you started working as a professor.
> I would have expected a higher percentage.
This. A 60% stay rate evokes scenarios of academic inbreeding and a total disconnect between the real world and the small bubble where research groups operate.