You are a manager for a liquor store. Your store's computer keeps track of sales of liquor per customer. The mean amount μ 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 $__________."