This should be changed to "50k+ municipalities". The only way to get 100% was to ignore the title, since several of them are not cities by any reasonable definition.
As already stated, this is NOT a quiz of biggest cities as Nordre Follo and Bærum is a minicipality, the "cities" of these areas are called Ski and Sandviken respectfully. Also, Bærum, Asker and Nordre Follo has grown together with Oslo, so it's concidered a part of Oslo city