I recently bought a case of this oil when it was on sale at Kmart for $1.80 a quart. I wondered at that price how much synthetic it contained. Today I spoke with a guy in the laboratory at Smitty's Supply in Roseland LA, and he told me the figure is 10% synthetic. Even though it's rated SN, that low percentage is disappointing. I suppose it's the old saying: you get what you pay for?