Hah, that one is funny. The numbers for Stockholm look really weird. Groceries is at index 110, but rent at 27. This is true and a result of decades of political rent control, but what the numbers don't tell you is that it's impossible to actually get a decent apartment for rent. It's a completely dysfunctional market.

If they would have factored in the costs for buying an apartment or a house, it would look a lot more sane, and you would get numbers that are closer to what you would expect.

There's definitely significantly different methodology here since, Buenos Aires is one of the cheapest cities on the numbeo list and most expensive on the article.