America Productions uses a process costing system. Its Belting Department's Work in Process inventory account at March 31 consists of 7,000 units that are 100% complete with respect to materials and 70% complete with respect to conversion costs. If the total conversion cost in the Work in Process inventory account is $552,000 at March 31 and the cost per equivalent unit for conversion costs is $6.00, how many units were completed and transferred out during March