About 85 percent of all the merchandise sold by wal-Mart was shipped through its distribution system to its stores. (Competitors supplied to their retail outlets on average less than 50 percent of the merchandise through their own distribution centers.) Wal-Mart used a "saturation" strategy for store expansion. The standard was to be able to drive from a distribution center to a store within a day. A distribution center was strategically placed so that it could eventually serve 150-200 wal-Mart stores within a day.Stores were built as far away as possible but still within a day's drive of the distribution center; the area then was filled back (or saturated back) to the distribution center' Each distribution center operated 24 hours a day using laser-guided conveyer belts and cross-docking techniques that received goods on one side while simultaneously filling orders on the other.