And what do we find? Despite having, by far, the highest population in the state, Salt Lake City is nowhere close to the top of the list. Even though SLC hasn't been growing anywhere near as fast as these other cities, it is extremely odd that South Jordan built almost five times as many units as SLC in 2012 but only added about twice as many residents from 2010-2012 (5516 versus 2874 for SLC). This lack of SLC construction is what's pushing up prices, and driving people and businesses to other cities in the valley.
Note: except for a single large complex (which I've yet to identify) that opened in SLC in Oct 2012, these SLC numbers would have been quite a bit more dismal. Also, for likely explanations for the lack of building in SLC, see this post on historical preservation and this one on SLC's strangely specific parking minimums.