Comparing generally literate nations (as in not some backwater African country with little to no educational system), I believe that more people would allow for a greater number of illiterates. Granted, those "extra people" could tip the scales either way, but it would seem that neither we, nor the people conducting the study know the specifics. I'm basically saying that between nations with similar levels in educational standards, a nation which supports a significantly larger number of people will have a harder time educating that many people. A smaller nation might have enough money to properly educated most of its citizens while a larger one will have to expend a lot more cash to accomplish the same goal. Of course, the US *should* be spending more on education anyway, but obviously that has not been the case as we've been spending our money elsewhere.