Thank you. Looks like they ask 18 000 people at random yearly. Quite a good sample size for a country of 10 million citizens. But I'd take it with a scoop of salt as it's self reported and other numbers are weirdly worded if not wrong. I recall cigarettes being 38 SEK for a pack in 2008. Now they're 78 SEK, which is far more than +45% and in a shorter time span.

Edit: found the summary. 30% are still using nicotine, allegedly.