From what I could quickly google, there is this report from The Swedish Council for Information on Alcohol and Other Drugs [1] which says that at least for students the number is 50% lower than EU average (p. 28).
Don’t believe the lies from the Swedish anti-drug organizations. They are fueled by religious zeal, not science.
It is probably true that Sweden has a below average cannabis usage, compared to the rest of Europe, but recent studies from the Swedish customs(?) show much higher numbers.
Smoking pot in Sweden is incredibly taboo - so those who do keep their mouths shut about. Still plenty of people do it, we had the internet early on and could see through the propaganda.
I was fairly open about smoking(and growing) while I lived in Sweden so I got to know and discuss this issue quite well. It is one of the reasons I no longer live in Sweden - on paper it is free and democratic, but if you go against the group think there will be consequences.
[1] https://www.can.se/app/uploads/2020/01/can-rapport-163-drug-...