The bar graph indicates sales figures for reading materials from 2002 to 2012. Write a report to a university lecturer describing the information shown below.

The bar chart shows the sales figures of four types of books (hobbies, entertainment, history, and art) from 2002 to 2012. Overall, history books had the highest sales during the whole period, while hobbies books remained the lowest. Entertainment and art books showed a gradual increase, but they never reached the level of history books. […]