While skimming this Wikipedia article about Jewish populations by country, I noticed that Stockholm is a lot higher up on the list than I would have expected. With approximately 9,000 Jews, Stockholm has the 15th largest Jewish population among European cities; and if you were to take France out of the equation (i.e. Paris, Marseille, Strasburg, Nice, Lyon and Toulouse), Stockholm would be among the top ten European cities. According to one estimate, the Jewish population of Stockholm may be as high as 14,000.
According to the European Jewish Congress, there are also significant Jewish populations in Gothenburg and Malmö. A large portion of the country's Jews descended from refugees and immigrants from Hungary, Poland, Denmark and the former Soviet Union.
Although not a very scientific statistical sample, I took a quick glance at our tallit orders from Sweden over the past year, and found that one-fourth went to customers in Stockholm.
What are our Swedish customers buying? A fairly even mix of tallits, tzitzit and tefillin.