The charts show how changed the number of sold books from 1972 to 2012.
The charts show that from 1972 to 2012 the percentage of sales of Adult’s fiction books increased more than twice. At that time the number of sales of others declined twice. The sales of Children’s fiction books in 20 years from 1972 to 1992 increased only for 2 percent and in 2012 the percentage of sales was 25%, so the common incline is 5%. Number of customers who bought biography books in 1972 was 20%, but they were getting fewer by each year and after 20 years the sold percentage was 15% and in 2012 it was only 8% which is the lowes indication for that year. The number of people who prefer travel books decreased significantly from 15% to 10% by 40 years.
In conclusion we can see the number of sales of Adult’s and Children’s fiction books significatly icreased as the other type of books decreased.