Prices that are lower than justified by the costs have helped keep the local exchange a monopoly; prices that are higher have helped create the competitive long-distance market. The subsidy from long-distance to local was and continues to be accomplished by manipulation of the access charges the local-exchange carrier can impose for access to its local loop. This access charge is called the carrier's carrier charge or the carrier common line (CCL) charge. In the 1980s the FCC enabled phone companies to move to greater cost-based pricing of long-distance service by the introduction of the subscriber line charge (SLC), added to every phone bill regardless of the number of long-distance calls made. Large customers had already been given special treatment through 'special access' tariffs for private lines. Much of the domestic price decline has been attributed to decreased access charges paid by AT&T, with savings passed through to customers, as required by the FCC.