§ 1. Gross return consists of surpluses, depreciation and interest.
§ 2. The National Coal Board, 1965–66, figure is calculated after allowance for the capital reconstruction carried out in that year. The average is in respect of the Board's accounting years 1961, 1962, 1963, 1964–65 and 1965–66. Because of the change in the Board's accounting year the return for 1963 has been assumed to be 12/15th of the figure for the fifteen months period ended March, 1964.
§ 3. The Gas figures are for England, Wales and Scotland; the Electricity figures for England and Wales only.