Fig. 121 has been drawn to assist in proving the preceding statement regarding curve slope. Starting with one dollar, it was assumed that a uniform increase of 10 per cent of the accumulated amount would be made at the end of each year. This is the same as though the dollar were placed at 10 per cent compound interest. At the end of thirty-six years it can be seen that the one dollar has increased to nearly

thirty-one dollars. Though the ^'^- ^f • Curve Showing the Growth •^ , p 1 • 1 1 of One Dollar at lo per cent Cornaccumulated fund IS shown by a

smooth curve throughout the period of thirty-six years, the curve is constantly changing its slope in spite of the fact that the rate of increase remains constant at 10 per cent per year. The curve in Fig. 121 is very similar in shape to the curve for the United States in Fig. 120. This similarity in shape shows conclusively how much the reader would be misled if he should assume that the increasing slope of the curve in Fig. 120 proved in itself an increase in the rate of growth. The actual percentage rate of the growth for Fig. 120 can best be studied by making an entirely new chart for the purpose of observing percentage rates only.

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