The Postal Accountability and Enhancement Act of 2006 requires the United States Postal Service (USPS) to report to the Postal Regulatory Commission on the level of service performance provided by each market dominant product. The Postal Service™ measures service performance in terms of speed and reliability. Single-Piece First-Class Mail includes letters, flats, and parcels and is measured from collection box drop point to delivery. Presort First-Class Mail® includes commercial mail prepared by the mailers which is sorted to the finest extent required. Single-Piece First-Class Mail® International provides a measure of the domestic leg of travel for single-piece international mail.