It is estimated that some seven hundred million people about half of the world's population are unable to read and write, and there are probably two hundred and fifty million more people whose level of attainment is so slight that it barely outlives a literacy. Recently the attack on illiteracy(文盲)has been stepped up. A world plan has been drawn up by a committee of UNESCO experts in Paris, as part of the United Nations Development Decade, and an international conference on the subject has the aim. People must learn the basic skills of responsible citizenship: the ability to read notices, newspapers, timetables, letters, pricelists, to keep simple records and accounts, to sort out the significance of the information gathered, and to fill in forms. The major areas of illiteracy are in Asia, Africa, and Central and South America. In Africa there are at least one hundred million illiterates, compromising(牵连)eighty to eighty-five per cent of the total population. In Europe the figure is about twenty-four million, most of them in Southern Europe, with Spain, Italy, Portugal, and Yugoslavia heading the list (the United Kingdom has about seven hundred thousand). Studying carefully the clues in the passage, we learn that the total population of Africa is ______.