The pie charts below show the percentage of five kinds of books sold by a bookseller between 1972 and 2012

Provided is the pie chart illustrating data regarding certain types of books sold (measured in percentages) by a bookman from 1972 to 2012.
Looking from an overall perspective it is readily apparent that the demand for adult fiction and children’s fiction increased in the given period while others and biography showed a complete reverse trend.
Looking at the most popular books sold, adult fiction and children’s fiction proportion shared a common trend with 20% sale. Initially, adult fiction was at 20% in 1972 while it reached to 45% after 40 years period. children’s fiction rose slightly by about 3% from 1972 to 2012.
Turning to consecutive infamous books in the period surveyed, biography and travel books initially accounted for 25%, 20% and 15% respectively, then, in 1992, the preference declined gradually by around 5% for each category , travel book being the exception with minor difference and subsequent 8% drop for all three books