The measure of the variety of choices offered to consumers by a store, based on the diversity of its products, is called the service rate. The absolute service rate is determined by comparing the number of products available in the store to the total number of products on the market. The relative service rate, on the other hand, is calculated by relating sales volume to demand volume. For example, if a store offers six coffee brands out of the twenty-four available on the market, its absolute service rate is 25%. However, if these six brands represent 40% of sales, the relative service rate is 40%.