Probably another one-third may be added to this total to represent average logistics costs for the firm at about 11 percent of sales. Over the last decade, physical distribution costs have ranged between 7 percent and 9 percent of sales. There may be a trend of increasing costs for individual firms, although Wilson and Delaney show over the same period that logistics costs as a percent of U.S. GDP have declined by about 10 percent. Logistics costs, substantial for most firms, rank second only to the cost of goods sold (purchase costs) that are about 50 percent to 60 percent of sales for the average manufacturing firm. Value is added by minimizing these costs and by passing the benefits on to customers and to the firm’s shareholders.