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If it's a gasoline engined vehicle with an auto trans, the difference may be relatively small as the engine operation with more throttle is more efficient which tends to mask the extra energy necessary to push the air out of the way faster.

If the energy fraction used for things other than pushing air out of the way is relatively large (A/C on, fat tires, disk brake drag at all four corners, heavily preloaded bearings, power steering and automatic hydraulic pumps, heavy vehicle, etc.), then the percentage effect is also reduced.