Shawn M. Halversen (paraphrased)
I asked him about the time between each of the original 99 desolations.
Brandon Sanderson (paraphrased)
It turns out that the number 99 in the stories was made up, and that there were much fewer of them. He also then stated that the cosmere runs along a 10,000 year gap and that Roshar falls right into the middle of the timeline. He ended with "That should give you a perspective of the timeline and events of the desolations".