I quoted the estimates given by a physicist on the NOVA program yesterday.
Correct me Iif I'm wrong, but I think he was the MIT professor.

Yes, less than one percent of the potential energy appears small.

So I did some checking up and it's more or less correct.

You see the potential-energy within gasoline is quickly wasted on factors such
as friction, heat loss, air resistance, inertia, gravity [going up hills], accelerating
and maintaining the cruising speed of all that steel glass and rubber, uneven travel surfaces, improper tire inflation, incomplete combustion in a nitrogen-oxygen atmosphere and
even braking and slowing are potential-energy wasters.

I'm still shocked but now I understand.
We are dealing with mechanical and chemical technology that is over 100 years
old.