Thales sins Katas eves, S.A., of Greece makes marine equipment. The company has been experiencing losses on its bilge pump product line for several years. The most recent quarterly contribution format income statement for the bilge pump product line follows: Common costs allocated on the basis of machine hours. common costs allocated on the basis of sales dollars. Discontinuing the bilge pump product line would not affect sales of other product lines and would have no effect on the company's total general factory overhead or total Purchasing Department expenses. Required Compute the increase or decrease of net operating income if the product line is continued or discontinued. (Decreases should be indicated by a minus sign.)