Different engines have different oil consumption, but it will also depend on many other factors, such as driving style, terrain, driving conditions, load, engine condition, whether its being driven more in an urban environment or on the highway, etc.
The closest determinant is that the normal consumption is the one recommended by the engine manufacturer. However, this information is not stated explicitly, but only in the form of an upper limit for consumption.
For more information, visit the Advice & Proposals section.