The net result of the galaxy of revolutions in the way men organized their economic life was that continuous economic change came to be part of the natural order of things and that the scale of the economy began to expand perceptibly and without limit. It was within the century 1750—1850 that the crucial transformation took place that led eventually to a sustained growth in incomes per head. It is difficult at this distance in time and with the sketchy statistical data at our disposal to calculate precisely when this sustained growth began, how much it amounted to and how rapidly it developed. But analysis and interpretation of the existing statistical series suggests a certain pattern, and this pattern is probably reliable enough even if the precise figures are questionable.

Somewhere about the middle of the eighteenth century there is evidence that total national output began to grow—perhaps not faster than it had ever done before in earlier decades, but certainly faster than it had over most of the preceding century. At this stage, however, population had also begun to grow, and it is doubtful whether output was growing any faster than population at the beginning of the period, and hence whether incomes per head were growing at all. In the last quarter of the century, however, the evidence for an improvement in incomes per head becomes much stronger, though it is still not conclusive.