Paperwork further increased the number of desk workers, whose work surfaces diminished in size as office rents rose, and the paper itself was moved more and more directly to filing cabinets or sent to specialized records management centers, or transformed into microfilm, or both. Modular desks seating several co-workers close by became common. Even executive or management desks became mass-produced, built of cheap plywood or fiberboard covered with wood finish, as the number of people managing the white collar workers became even greater.