There absolutely is a level 5. It was defined and measured in the survey. Both links confirm that.
But then they did not break it down in the reporting because few enough people fell into it for their survey to produce reasonable statistics on a per country level.
Now you are correct that I should not have said "under 2%". But given that the portion of the USA at level 4/5 matches the international portion at the same level (both cases 12%), it seems likely that the portion of the USA at level 5 (which the survey was not large enough to estimate) is about the same as the international average (which the survey measured at 2%).
Therefore even though the survey did not report a figure for the USA, it is likely that the real figure is around 2%.
I stand by my belief that this terms of service is sufficiently complex that even fewer can understand it.
You are right that the average Prezi user is more likely to be literate than the average American.
This figure is meaningless, which is part of why they didn’t report it. You’re fixating on a number that doesn’t inform you.
Whatever their level 5 means, it excludes at least 90% of the people who wrote large technical and impenetrable documents just to graduate from school, not including all the practicing lawyers, doctors, engineers, scientists, and writers in the country.
There’s a disconnect between using the 2% number to represent any kind of literacy threshold, and reality. It may have measured something, but this “2%” does not represent a limit on number of people who have the capability to read Prezi’s terms of service.
> I stand by my belief that this terms of service is sufficiently complex that even fewer [than 2%] can understand it.
That’s unfortunate, I’ve failed to make a convincing argument. I was hoping to help you see more clearly that’s not what your data actually says, and is also contradicted by other data as well. The data isn’t wrong, but your interpretation is.
It is clear that the earlier claim "under 2% of Americans read beyond a grade 12 level" is not true, and not what your supporting links actually say. It's absolutely clear that your speculation "Odds are than under 1% could read that [Prezi's] terms of use and actually understand it." is both not true and dramatically pessimistic.
Yes, legalese is dense. Hardly anyone reads it because it takes a lot of time, not because nobody is capable. How many people read below a 12th grade level (whatever that means) are using Prezi in the first place?
I'm just pointing out that your initial interpretation of the data was off by an order of magnitude.