Too long for a comment:
I wonder how meaningful an average would be considering a rocket goes from 0 to 6 gs during launch.
It doesn't help that acceleration depends on the wildly variable mass of the rocket. Fuel accounts for the bulk of the weight, and most of it is gone two minutes into flight.
Nor does it help that the rocket gradually pitches down from vertical to horizontal. Close to vertical you lose close to 1g just counteracting gravity, and close to horizontal you lose close to nothing.
So even when you simplify by ignoring drag and other details of launch, the basic physics you're left with still make it very challenging to estimate things like acceleration---and therefore averages of those things, to the extent that they're meaningful :)