Mercer Island is Third-Weathiest Zip Code in Puget Sound for 2012

What's in a Zip Code? If you're a Mercer Island resident, it's a significant amount of wealth, according to the Puget Sound Business Journal.

Based on estimates of average household net worth in 2011, Mercer Island's 98040 zip code ranks third in the business-focused newspaper's 2012 ranking, just behind South Sammamish in the 98075 zip code. Mercer Island's average net worth is $578,614, while South Sammamish has an average net worth of $602,308.

Medina's 98039 zip code again ranked as the Puget Sound's wealthiest — which counts Bill Gates as one of its residents, among others — a position the wealthy enclave has held since the PSBJ started the ranking in 2005. Medina has an average net worth of $737,498. That's down 11 percent from 2010, when Medina's average net worth was estimated at $830,068.