In the first two columns the percentages given relate to the operating expenditures alone, without reference to the total expenses--eliminating, that is to say, the large group of fixed charges, and treating these operating costs entirely by themselves as if the others were non-existent. In the third or right-hand column, it will be observed, the main groups are again given in percentages, not of the operating expenses alone, but of the total outgo, including capital expenditures in the nature of fixed charges. It should also be noted, of course, that only a few of the large or more important items are here included, and in the right-hand column no details, other than for the four main headings, have been computed. The constancy in the distribution of these groups of railroad expenditures over a term of years is graphically shown by the opposite diagrams.[32] The perpendicular line for each year is divided proportionately to the relative importance of each designated item of expense for that year. Thus the course of the horizontal lines, dividing the four main percentage zones, represents the ups and downs in the relative importance of each item. Occasionally, as in the years following 1895, the proportion of so-called general expenses decreased appreciably; but, in the main, all the items moved more or less in unison subject to the movements of wages and prices. This relative constancy proves how fundamental the arrangement of groups is. The attempt to differentiate the constant from the variable expenses of railroads on the basis of the foregoing operating statistics may now be made. What proportion of each item in the table for each of the large groups is fixed in amount; and what proportion fluctuates more or less in connection with the volume of traffic?