On a shopping trip, Melanie decided to buy a light blue coat made from woven fabric. A tag on the coat stated that the price was $79.95. When she brought the coat to the store's sales clerk, Melanie was told that the coat was on sale, and she would pay 20% less than the price on the tag. After the discount was applied, Melanie paid $63.36, $15.99 less than the original price. The value of Melanie's consumer surplus from this purchase is what?