Use "margin of profit" in a sentence

1. If they got the `job' it often showed such a small margin of profit that Rushton used to grumble at him and suggest mismanagement

2. This analysis would serve to raise the question: (1) if, since the end of the war, steel production has been transformed from a reasonably prosperous into a relatively unprofitable industry and (2) if this transformation is due in good part to excessive reinvestment of earnings in additional plant, thus creating a condition of overcapacity with resultant reduction in the margin of profit