It is VERY clearly explained in a number of different places and on the FairTax website.Why does it have to be explained even once?...How many times do you have to have you state sales tax rate explained to you?
It's there, Looey, for those like you who like to pretend there is some dishonesty in quoting it one way or another (as you typically do).
It's explained clearly enough on the FairTax site so that only a moron would fail to understand it.