“Statistical area” means an area established by action of the policy committee for purposes of determining the maximum acquisition costs for an owner-occupied housing unit to be financed pursuant to Part 6 (commencing with Section 52500). Such areas shall be any one of the following:
(a) A metropolitan area.
(b) A county which is not within a metropolitan area.
(c) A grouping of counties as determined by the policy committee, which are not within a metropolitan area, if insufficient recent statistical data exists for the purposes of this division for any county within such grouping.