cityboy
ArboristSite Operative
Not even close here, but the relationship may be different in North America - regular fuel is 95 octane here, and premium is 98, buth unleaded.
the octane rating systems for the US and Europe are different, so the numbers can't be directly compared without understanding the rating systems.
the US uses the average of the Research Octane and Motor Octane ratings, typically indicated as R+M/2 on our pumps. Europe uses Research Octane only, which typically runs around 10 pts. or so higher than Motor Octane ratings, but I don't remember exactly so it could be slightly more or less than 10. Taking that into account, the European octane content is very similar to that in the US, within a couple of points at the most.