Estimates in published tables are based on data from the Service Annual Survey and administrative records. To maintain confidentiality, no estimates are published that would disclose the operations of an individual firm. The total error of a published estimate may be considered to be comprised of sampling error and nonsampling error. Individuals who use Service Annual Survey estimates to create new estimates should cite the Census Bureau as the source of only the original estimates. See technical documentation for additional information on the Service Annual Survey.