By the 1980s, according to international but admittedly inconsistent definitions of literacy, about seven out of ten adults in the world were considered literate. The increase in literacy from ancient times to the present has not been a story of unbroken progress. The ability of people within a given society to read and write has been influenced by a number of factors, including economic well-being, the availability of material to read, the amount of education available, and the basic matter of the usefulness of reading. Of these factors, usefulness has probably been the most decisive. In ancient societies, as people settled into stable patterns of agriculture and trade, it became useful for some of them to read and write in order to keep records, to transact business, and to measure amounts of land, animals, goods, materials, and produce. Since all economic aspects of a society were closely tied to the operations of government, literary became useful and even necessary for the keeping of records by officials. The responsibilities of citizenship led to a fairly high level of literacy in ancient Greece and Rome, but in addition to that, there also grew an appreciation of good literature, poetry, drama, history, and philosophy. During the early Middle Ages, with the general breakdown of society in Europe and the decrease of commerce, literary became largely confined to the church. But in the late Middle Ages, in the period of the Renaissance, the great expansion of commerce and banking led to a revival in literacy for the same reason that had caused it to increase in the ancient world usefulness. With the invention of the printing press and inexpensive paper late in the 15th century there was for the first time a great availability of reading material for a much greater number of people. Religious reformers were among the first to utilize the situation, quickly getting translations of the Bible and educational tracts and booklets into the hands of many people. The broadened religious enlightenment that resulted was followed in later centuries by a political one. Political theorists who favored doctrines promoting the natural rights of man called for an attack upon illiteracy. Political revolutions, particularly in the United States and France, helped inaugurate an era in which all classes were called upon to become informed on public policy for their own welfare. Against this political background there emerged the movement for universal popular education. Literacy came to be understood as a means whereby the individual could benefit and advance, and gradually whole societies began to acknowledge that universal literacy among their citizens was an avenue to greater economic well-being. From the first paragraph we learn that