Should read:

. . Prudhoe Bay Field, the largest oil field in North America, every 60 days.

Phew! For awhile you had me worried.
Right, I mean 60 days we can live with, but thirty days seems like an awful short time!  :)
And let us not forget that this is all based on CURRENT levels of use.  In order to have the economic growth required by our economic system we have to use even greater levels of energy in the future or "the system" will break down.