Sac Bee's inclusion of Amador County housing numbers

For the longest time, the Sacramento Bee has only provided housing information (sales, prices, etc.) for the four county region of Sacramento, El Dorado, Placer, and Yolo. Granted, the Sac Bee's numbers usually come from one of two sources, San Diego-based DataQuick or Folsom-based The Gregory Group.


Recently, I've begun seeing DataQuick's numbers include additional counties, including Amador:

"March escrow closings for all homes in the region totaled 3,223, beating January and February, but still a "tepid" opening to the spring sales season, said Andrew LePage, an analyst with La Jolla-based DataQuick. The numbers were down from 4,571 recorded the same month last year in Amador, El Dorado, Nevada, Placer, Sacramento, Sutter, Yolo and Yuba counties.

March closings represent sales started in December, January and February before extensive publicity about imploding subprime lending firms and tougher new lending rules."

I have to play a little devil's advocate here, but are the year-over-year comparisons looking at this year's 8 county numbers versus last year's 8 county numbers, or just last year's 4 county numbers? Next, if the YOY comparisons are correct, does the inclusion of the additional counties improve the numbers in favor of market conditions deteriorating or improving?

As a frame of reference, I first started noticing the 8 county figures in a Sac Bee article noting the spike in foreclosures at the start of the year (2007).