The two pie charts illustrate changes in the proportions of pollutants entering a specific area of the ocean over a ten-year period between 1997 and 2007.
Overall, it is evident that air pollution accounted for the most significant share throughout and showed a considerable decrease. Domestic sewage and offshore oil exhibited an upward trend. Conversely, marine waste, industrial waste, farm waste, and litter witnessed a downward trend until the final year.
According to the pie charts, domestic sewage grew remarkably from 18% in 1997 to 29% in 2007. Also, offshore oil made up exactly 5% in 1997, followed by a soar to 14% in 2007.
In contrast, the figures for marine and industrial waste experienced a noticeable fall from 22% and 17% in 1997 to 17% and 9% in 2007, respectively. Moreover, farm waste declined dramatically from 4% to 2% at the end of the surveyed period. Although the amount of litter remained at 4% in the initial year, this figure reached a low of 0% in 2007. Finally, air pollution decreased minimally by approximately 1%, before ending at 29% in 2007.