Wellllll, I can't edit it anymore, but yeah, got that totally wrong (original source was a real estate developer who's involved with a couple of the projects).
I suspect he took "about 60% more than any other city" and radically misinterpreted it (and I went and parroted him -- oops). Original conversation was right around when this article was published: https://www.seattletimes.com/business/real-estate/seattle-ha...
Got a source for that? https://archpaper.com/2017/08/booming-seattle-dominates-nati... puts it closer to 20%, although that's only counting fixed cranes...