Yes... it would be better to have used number of primary students, instead of total inhabitants. I will try to redo it later with this modification.

You must understand that it's not quite easy to find that data. If you visit the unesco database where i take from the data, there are rar missings like for example Canada number of teachers !? So, i can imagine that it will be more difficult to get the number of primary students.

But i would like it. Sure. Thanks for note it.

Responding to your first question: in education science is quite relevant the number of teachers per student. This was my target to explorer.

For me, the most unexpected result is that in this top-20 there is countries of any continent and size. This rarely happen with other "market metrics". I've curiosity to see the rank using the number of students instead the number of inhabitants. I suspect that it will not be so many differences. It only will be more accurate.

It could be possible instead, to apply a correction factor using the "life expectancy" too. Because in countries with more life expectancy, the % of students is lower per inhabitant than in countries with less life expectancy.

Thanks again.