The culminating development, still in progress, was the development of industrial technology, the application of mechanical sources of energy to an ever-increasing number of production problems. By about 1800, the agricultural population of Britain had sunk to about 1/3 of the total. By mid-19th Century, all the countries of Western Europe, plus the United States of America had more than half their populations in non-farm occupations. Even today, the Industrial Revolution is far from completely replacing agrarianism with industrialism. Only a minority of the world's people today live in industrialized societies although most predominantly agrarian societies have a significant industrial sector.