The graph shows the number of books printed in Europe between 1400–1800. Bar graph of European output of printed books from the 15th through 18th centuries. Copies are measured in the millions. There are less than 100,000,000 copies in the 15th century; 200,000,000 copies in the 16th century; 500,000,000 copies in the 17th century; and almost 1,000,000,000 copies in the 18th century. A conclusion that can be drawn from the graph is that the demand for books increased slightly between the fourteenth and fifteenth centuries. slightly between the seventeenth and eighteenth centuries. sharply between the sixteenth and seventeenth centuries. sharply between the eighteenth and nineteenth centuries.