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 cen-ters.) 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.