The graph shows how products were sold during 2009. In general, product B and product D are becoming less popular while product A and product C have increased hugely in popularity.
Product B was the most popular fat at the beginning, and its value of sale reached a peak of $50, 000 in January. After this, there was a rapid decrease. However, usage of product A increased significantly in January although it was not popular at the first time, at $5,000.
To begin, product A and product C followed a fairly similar pattern during 2009. These products were sold less than others in January, at $10,000 and $5,000, respectively, and their value of sales rose slowly in the next months. Unlikely, both of them were with higher in vales of sales In December, at $50000, and about $50000 respectively.
By contrast, product B and product D decreased slightly. Product D remained steadily at $20, 000 during the year, and its usage was the lowest in December. However, Product B was more common than product D, and then dropped dramatically, from $50,000 in January to $25, 000 in December.