According to the pie chart, (comma) the main cause of global land degradation was overgrazing (no gap necessary), reaching 35% of the total causes. In addition, deforestation was on the same range of levels as overgrazing, around 30%. Last but not least, overcultivation and other causes were the rest 28% and 7% respectively, which renders both of those causes as secondary roots of the problem.
From the data contained in the table, it can be seen that Europe had the highest level of land degradation, around 23%, and that’s mainly due to the fact that its (no apostrophe) influence/ OR better: the destruction by deforestation and over cultivation was significant, reaching 9.8% and 7.7% respectively. However, Oceania possessed the highest percentage of over grazing, at 11.3%, and the lowest percentage of overcultivation which amounted to 0%, while North American land was affected by those two phenomena by 1.5% and 3.3% correspondingly.
Taking everything into account,global land degradation was well distributed (this statement is unclear- do you mean among the 3 countries?), and over
the 50% was caused by over grazing and deforestation, whereas there were numerous fluctuations among the regions.
Note: do not just report data; make some more comparisons, as well.