Indeed. Because they left the Catholic Church does not mean they do not currently have one.
When I lived in Switzerland, there were only two choices: Catholic or Reform (with Reform being analogous to our Lutheran). Whichever church you belonged to, you had to pay an extra church tax, and even back then believers formally left churches to avoid the tax. So...
In 2015 the Eurobarometer found that Christianity was the religion for 47.6% of the respondents, with Protestantism being the main denomination with 36.5%, followed by other Christians with 8.6%, Catholics with 1.6% and Eastern Orthodox with 0.8%. 31.0% of the sample declared to be Agnostic and 19.0% declared to be atheist.[11] - https://en.wikipedia.org/wiki/Religion_in_Sweden#Surveys