The Wealth of Nations by Part 2 Chapter 3 Page 15

ten per cent, and their profits must have been sufficient to afford this great interest. At present the rate of interest, in the improved parts of Europe, is nowhere higher than six per cent, and in some of the most improved it is so low as four, three, and two per cent. Though that part of the revenue of the inhabitants which is derived from the profits of stock is always much greater in rich than in poor countries, it is because the stock is much greater: in proportion to the stock the profits are generally much less.

That part of the annual produce, therefore, which, as soon as it comes either from the ground or from the hands of the productive labourers, is destined for replacing a capital, is not only much greater in rich than in poor countries, but bears a much greater proportion to that which is immediately destined