Zillow grows database, boosts 'Zestimate' accuracy

Site's margin of error shrinks to 8.5% nationwide

Property search and valuation site Zillow has expanded its property database and improved the accuracy of its "Zestimate" home valuations, the site announced today.

Zillow has added more than 25 million new Zestimates to its database, bringing its coverage total to about 100 million homes, or more than three-quarters of all homes in the country, the site said.