Based on the table "Fatty acid composition of some common edible fats and oils" from http://www.scientificpsychic.com/fitness/fattyacids1.html, 85% of the total fatty acid residues of olive oil are fatty acids containing 18 carbons in their structure.
These fatty acids are stearic acid (3%), which is saturated, oleic acid (71%), which is monounsaturated, and linoleic and alpha-linoleic acid (10% and 1%, respectively), which are polyunsaturated.
