"Spain has the most, Italians sell it the most but.. Greek quality is the best" :)

 The extra-virgin olive oil type is certainly the best type among all. It is extracted by cold-pressing method to prevent the natural content from being altered by exposures to high temperature. This grade of Oil will have the lowest acid content compared to its standard virgin counterpart. It is considered the best simply because it retains most of the natural flavor and aroma. This is as well the most commonly used type of olive oil for health purposes. You can even consume or drink extra virgin olive oil directly without any other ingredient mixed with it because the health benefits of olive oil are extensive. 

 The virgin type of olive oil is an unrefined form. It is extracted by cold-pressing method, and it brings more natural aroma and flavors compared to the aforementioned types above. It contains slightly high acidity content between 1 to 4 percent. This specific type of olive oil is temperature resistant as well. Compared to the extra virgin type, this one has milder taste. This is suitable for low-heat cooking purposes. 

 Although the name clearly suggests that it is pure, this type of oil is not at all pure. In fact, it is a blend extra virgin or virgin type olive oil with a refined form of olive oil. The blending method is often used when the extraction quality is not as good as expected. In order to improve the quality, the refined oil has to be mixed with a better quality one, either extra virgin or virgin type of olive oil. The added oil will give higher amount of vitamin E and better flavor. 

The pomace type is extracted from the residue that remains after the fruit is pressed. After the actual fruits are pressed, they leave residue containing oil and water. Once the water and oil are removed, the residue still contains certain amount of oil and can be extracted. Since it is extracted merely from residue, virgin oil is mixed to help to improve the quality. Due to this charecteristic, it is the least expensive and has the highest cloud point which makes it suitable for high-heat cooking.