The automated data collection system for a manufacturing process will record data for 25,000 parts per day. Assume that, when stable, a certain process will operate with a nonconformance rate of 37.6 NCPPM (nonconforming parts per million). If the nonconformance rate per day is to be monitored using a control chart, what type of chart would be used? Choose a P, U, or X-Bar/S Charts, and explain in a few words.