The USAGE clause specifies the internal format of a data item or
  represents the address of data in a COBOL program.

  Format -

                { BINARY          }
                { COMPUTATIONAL   }
                { COMP            }
                { COMPUTATIONAL-1 }
                { COMP-1          }
                { COMPUTATIONAL-2 }
   [ USAGE IS ] { COMP-2          }
                { COMPUTATIONAL-3 }
                { COMP-3          }
                { DISPLAY         }
                { INDEX           }
                { PACKED-DECIMAL  }
                { POINTER         }
                { POINTER-64      }