I know 8 swinger clubs of which 2 are full size dance/nightclubs combined with swinging and striptease. Then we have Harddrive at the western docks, underground club with room for hundreds of people. Mostly young girls and black men dancing and fucking on the tables. If you count Darkside clubs and private clubs in the vicinity of Malmö a bit liberally I think my numbers are not that much of. But might be a bit high, I admit. Since I dont really know! Its just a guess.
The thing is, if you count the Öresund as a region, which we always do, my numbers are low... Very low. Since you then count Copenhagen into it as well, and a lot of other citys that are very close. The whole area is like a big spread out mega city.
Oh and then we have the nude beaches that every county have at least one of. Payed for by the taxpayers btw. A lot of sex outside of the family areas! Last summer there were almost only black guys and white girls in those other areas. Im there a lot, lol.
So it depends on how you look at it.
Also remember that 25% of Swedish couples know what swinging is or have been, are, or thinking about taking it up. Of course, not many go to clubs but still...