I can't be sure - MV is our resident statto, and I'm sure has all the numbers at his fingertips.
I flew OSL-BRS and BRS-ARN-BRS last year, on weekday evenings, and was nothing short of staggered at how full the planes were. However, Load Factors alone don't necessarily make a route successful (I think the lead-in price on those flights was £29??). SK do at least have the advantage of not having fuel surcharges on their tickets, so their headline prices can be really pretty low.
I don't know how many people would want to take a Scandinavian break this summer. The costs in Norway were horrid even when the pound was strong.