I've been looking up the number of foreclosures in my area and I keep running into reports of the "foreclosure rate," but with very few articles defining what that means. In fact, the only complete definition I found was
The foreclosure rate is the share of mortgages in some stage of the foreclosure process. (link here)
However, some other half-definitions of "foreclosure rate" that I found seemed to indicate that the rate is normalized by the number of homes, not mortgages, in an area.
What, if anything, is the official definition of foreclosure rate?