Yes, but I mean income. Real Estate is pretty conspicuous by its nature.
The fact that this is so down voted supports my premise that this makes people uncomfortable. I don't have an agenda, I just think this is something people try very hard to hide.
(It's kind of useful when negotiating... "Public record valued your land at $200,000, and you paid $180,000 three years ago, but you want $750,000?")
You can also see a lot of this on Zillow and Redfin.