There are other types of olive oil, not virgin, obtained by mixing an oil extracted from the pressing of the olives and a rectified oil, which has undergone a "rectification" process (chemical or physical) aimed at eliminating defects (chemical and/or organoleptic). After being refined, the olive oil presents no defects in flavor when consumed. Since there is no regulation that establishes a minimum percentage of virgin oil to be added to the oily mixture, it is not possible to know the percentage of virgin oil compared to the refined one. The only certain thing is that the acidity is greater than 2% and can reach 3%.
It is therefore preferable to choose extra virgin and virgin olive oil which have high standards of control.