Do audiobooks count, if they don't get prose-book releases within the relevant time-window?

@Tulip No

How about anything he co-authors with Janci or Dan?

I'd say, any novel with his name on the cover, provided he contributed significantly to its writing, will count

My understanding of Skyward Flight (based on loose memory of a livestream) is that he gave Jancy an outline and they talked a lot during the writing process, but he didn't directly write any of the text himself because he was busy with other projects. His name is the primary one on the the cover, though.

Would Skyward Flight count if it had been released after this question was created?

@Joshua I'm going to say no. Just an outline doesn't count, substantial part of the actual text needs to be written by him

Seems fair to me.

YAY more fellow Sanderson enjoyers on the site!!

I would bet this significantly higher, however I hesitate because will undoubtedly be spending an increasing amount of time working on movie and TV production.

@DavidChee that said if another pandemic happens who knows how high the number could go LOL