I think he was giving an illustration, Bill.
He would probably estimate the universal functional fraction as something like 1 in 108, a figure I have seen cited many times in the forum. However, I invite @CrisprCAS9 speak for himself.
Estimating the fraction that could be applied to a particular function like mobility would be much harder, insofar as different kinds of mobility in different kinds of organisms have different kinds of constraints. In addition, the estimate would depend on the definition of the problem. For example, proteins used in metabolism are essential for mobility (how else to move a flagellum or limb?). Should genes with metabolic function, or regulation of metabolic genes, be counted?
Best,
Chris