Stationery Supplies is considering installing an inventory control system in its store in Provo, Utah. The store carries about 1,400 different inventory items and has annual gross sales of about $80,000. The inventory control system would cost

$12,500 to install and about $2,000 per year in additional supplies, time, and maintenance. If the savings to the store from the system can be represented as a fixed percentage of annual sales, what would that percentage have to be in order for the system to pay for itself in five years or less?