I'd like to second BooBoo's comments. The numbers look good because there is a story behind them.
My country isn't on the list but if it were, it'd be among the top few (in other surveys, it's almost always at or near the top). Here, kids "go to school" to go to school, meaning that they do a full session of school in the morning before moving on to tuition/enrichment schools the rest of the day and the weekend. I've always questioned the logic - children here are not in school to learn; they go there to get perfect grades because they've already learnt and practiced the questions ad nauseum in a cram school. There are model methods for math which reduces the need to think (remember - the goal is perfect grades, not learning, which can only happen if you make mistakes), even model composition essays to memorize or mimic from Grade 1!
Diversity of experience, creativity, experential learning, are not celebrated. But top marks, yes!
If only the twain will meet!
