Approximately one fifth of all silver produced in North America comes from recycled sources. A large percentage of this is recovered from medical x-rays. Essential Silver Incorporated (ESI) is a silver recycling business based in British Columbia. The company proposes to purchase and streamline a number of silver recycling businesses across North America using x-rays as their primary input. In order to do this, ESI must have a clear understanding of the quantity of x-ray material available and any fluctuations in supply that might occur.