The pie chart is highly correlated with the table, showing that there are three major reasons for the decline in worldwide land fertility but the influences were regionally situational during 1990s.
Globally, worldwide land degradation can be ascribed to four reasons, three of which, including deforestation, over-cultivation and over-grazing are more significant than other. That is, it seems that the affected areas due to all these three statistically resemble in proportion at nearly one third of the total, far exceeding that caused by other, which is only 7％.
When it comes to the table, it can be noticed that Europe with 23％ land affected suffered the most, followed by Oceania with 13％ and the least came North America with only 5％ land affected. Of all given regions, the influences of all three reasons were the most obvious in Europe, while were the least obvious in North America. Unlike Europe and North America, Oceania presented an one-sided situation, mainly because of over-grazing, which led to 11.3％ land degradation. Surprisingly, there was no over-cultivation but a little deforestation in this region.
