I should have added that it would probably go 7% for altitude athletes, 9% for sea-levelers.
Abebe was way way ahead of his time. You know this, but it should be said, that running a 2:15 marathon over cobblestones, barefoot in Rome's summer heat speaks volumes of his ability.
And then 2:12, much of it by himself, after a month of zero running, and doing it so relaxed. He said he could have kept running for atleast another 10k, easily.
I don't know the exact nature of the Athens course, but the winner just ran 2:15 there.