268,581 sq/mi X 640 acres/sq mile divided by 300,000,000 Americans = .153 acres per man woman and child
I do believe it was Rush who made this statement, and it was Americans, and not the world population
(268,581 sq mi) x (2,747,840 sq ft/sq mi) divided by (6,525,170,264 persons) = 1147.5 sq ft per person in the world, which is the equivalent of a square that is 33 ft 10.5 inches on a side.
Not much space, but it is a surprising result nonetheless.