""Retention rate is the ratio of the number of retained customers to the number at risk"." In contractual situations, it makes sense to talk about the number of customers currently under contract and the percentage retained when the contract period runs out." This term should not be confused with growth (decline) in customer counts. Retention refers only to existing customers in contractual situations. "In non-contractual situations (such as catalog sales), it makes less sense to talk about the "current" number of customers, but instead to count the number of customers of a specified recency." In a survey of nearly 200 senior marketing managers, 63 percent responded that they found the "retention rate" metric very useful.