I am ... confused.
Ehrman's Did Jesus Exist? has been criticized from various quarters for its sloppiness. But Akin here chooses to nitpick Ehrman's sources for literacy rates in Roman Palestine. It certainly seems that Ehrman's handling of his sources here isn't entirely adequate, but that's true of essentially the whole book and it seems odd to pick out this one instance. Akin in turn handles the same source at least as badly, giving a massively over-simplified account of Catherine Hezser's conclusions.
Perhaps Akin thinks he can build some kind of argument based on higher literacy rates, but in fact there are many lines of evidence suggesting that literacy in the region was lower than the Roman average even if the exact percentage can't be precisely determined.
Of course if Akin feels the need to rebut Ehrman's arguments in Did Jesus Exist? then he should by all means continue the project; but somehow I do not think that defending Jesus-mythicism is anywhere in Akin's list of goals.