This decline is probably related to the deregulation of transportation in the early 1980s and the development of inventory level management. Coyle et al. (2012) states that from 1985 to 2006, nominal GDP and the value of all business inventories both increased by 212.3% and 119.2%. Saving on inventory holding costs could add value to the inventory itself, so improving logistics productivity could bring growth to the economy by adding value to products. The leverage effect of purchasing profits can also support this point of view, because the decrease in purchasing costs will go directly into the network