Sarah is collecting data on a new brand of snack chip. One issue with producing the snack chip is its delicate structure, which tends to cause it to break in half during transportation from the dryer to the consumer package. The factory has implemented an automated sorting machine to remove broken chips before packaging. Sarah has developed a program that converts this data into a control chart, which displays the percentage of defective chips in the entire snack chip population. What type of chart has Sarah developed?