The driving force affecting affordability is lack of inventory. In both Snohomish and King counties it would take less than a week to sell the homes that are currently on the market. At the end of December, Snohomish County has just 210 single-family homes for sale in the entire county. Seattle had only 167 homes for sale; the Eastside just 55. That represented 70% less inventory for both Seattle and the Eastside as compared to a year ago. To give some historical perspective, the ten-year average inventory for the end of December is 545 homes in Seattle and 743 homes on the Eastside.