You are a manager for a liquor store. Your store's computer keeps track of sales of liquor per customer. The mean amount for sales per customer last month is not known. Based on your past experience, you are willing to assume that the standard deviation of sales amounts is $31. You take a random sample of 132 sales receipts. Apply the Central Limit Theorem and the 68-95-99.7 Rule to complete the following sentence: "About 99.7% of all samples will capture the true mean of all sales, in the interval of the mean plus or minus $__________."