Market & data
The state market review: the source buyers rarely open
Beside the quarterly price index there is a second official document: an annual market review published by the ministry in charge. It contains counts of completed purchases and county averages, from records, not from listing portals.

Two documents, two purposes
The ministry's annual review brings absolute figures: how many purchases completed and in which counties, while the statistics office's quarterly index measures price change over time.1,2
For a picture of one region the review is the more useful of the two: it shows how much trade a county actually sees, a figure no listings portal reveals.1
What to look for in the review
The most useful table is purchases by object type and county: it shows the ratio of flats, houses and land changing hands in the area you care about.1
Next to the counts stand average per-square-metre values from records, which can be placed beside asking prices of the same area to get a feel for the gap between asked and agreed.1