What is the average fuel consumption for a Dodge Ram 3500?

The Ram 3500, as a pickup with a GVWR of over 8,500 pounds, is not subject to official EPA fuel economy testing. Dodge does not list MPG in its specification sheets, and reviewers seem to avoid the subject. So most of what information is available comes from driver reporting on such sites as Fuelly. These may be imprecise but seem to indicate that gas 3500s average 12-14 MPG while diesels average 14-15 MPG.