FWIW, that's a cornmeal dusting in place of bench flour before sheeting. A world of difference between that and the laughable cornbread-pizza mashups you see in the early recipes on this site. I'd guess the bakers percent when used this way is like 1-2% or so. Maybe 3%.
Garvey, do you really think it's that high?
From my experience, he was three kernels of corn meal away from wrapping that dough around the roller. Hello, board scraper!
I would have used somewhat more, but do you really think that use could push it up to three percent?
My thought is that it may be some percentage by weight, but that the corn meal in that case is like sprinkles on a cupcake, they're there, but they just add a little crunch, no flavour.