The pie chart demonstrates the reasons that contributed to decreased agricultural efficiency globally, particularly in three different regions in the 1990s, namely: North America, Europe and Oceania. It is clearly seen that there are significant regional and causal variations.

The given pie chart demonstrates the vital causes of reduction of agricultural areas, Moreover, the table illustartes an impact of them on North America, Europe, Oceania during 1990s. The unit measured by a percentage. Overall, according to the chart, the main problem was over- grazing and followed by deforestation, so Cutting trees affects a great amount of lands to lose its productivity in Europe. The indicator shows that over-grazing leads to other factors, and amounted to 35%. Another main issue was deforestation 5 % less than the first one, consisted of 30%. Over cultivation was near to reducing trees, there was only 2 % between them (28%). Other reasons were equal 7%. This overconsumption had some effects in three countries. Deforestation effected more reduction of lands in Europe, constituted 9, 8 %. This proportion comprised of 1, 7 % and 0, 2 % in Oceania, North America. Over-cultivation affected only North America and Europe, consequently 3, 3% and 9, 8%. However Ocenia is the country which deforestation didn't caused land degradation, while it was the main victim of over-grazing, amounted to 11, 3%. That amount was 5, 5 % in Europe less 4 % than North America. At the end, Europe is influenced by all causes and totally 23%.