If all you have to go on is years of education, better to just call it “years of education” rather than pretending you’re actually measuring education. Having Russia in the same category as the Nordic countries is ridiculous.

It’s tricky to quantify education globally when there are different school systems that can’t be compared against each other. For example because there is no direct comparison that could be made against say… A college.

What is generally universal is university degrees but even those can vary wildly in quality. The same goes for having learned a job. Hell some countries don’t even accept university degrees from other countries because they don’t meet the local standards.

The thing about years or time spent in education is that people can spend additional years in education if they fail a class. And nine years of education may just be as good as someone who had ten years but failed in one year. It also doesn’t account for other differences like people that spent additional time in one year for additional education.

Anyhow, there is no simple way to quantify education. If you look at the percentage of people who graduated you may get a better idea but then you still need to differentiate between education systems and how many people in a given country actually got a given graduation. Even then it doesn’t tell you anything about how good the education actually is because education can be manipulated.