The pie charts illustrates the proportion of five types of books bought by a bookseller in three distinct years (1972,1992,2012).
From an overall perspective, the percentage of fiction’s books tented to increase dramatically while the amount of others ‘ books went down.
To begin, the ratio of adult fiction was the highest in 2012, had hend to increase quickly .From 1972 to 1992 ,the figure for adult fiction tended to increase slightly ,at about 5% and after 20 years, it shot up ,accounted for about near half.At the same time, the proportion of children’ s fiction picked up moderately , at about 5%.
Moving on to, the percentage of others tended to collapsed.From 1972 to 1992, it reduced slowly about 5% and the next 20 years , it continued to decrease ,at about 8%.During a 40 -years period from 1972, the figure for travel ,biography were lower and it tended to declined. The proportion of travel dropped gradually in 1992 about 3% and it continued to fell sharply after 20 years ,at about 10%.The ratio of biography collapsed in two decade , at about 12%.