From pp. 6-7 of the report:
There is evidence that some Europeans are leaving the church tax system, but there does not appear to be a mass exodus. The survey finds that between 8% of adults (in Switzerland) and 20% (in Finland) say they have left their church tax system. And, in several countries, one-fifth or more of current payers describe themselves as either “somewhat” or “very” likely to opt out in the future.
At the same time, majorities still support the tradition of paying taxes to religious institutions. Indeed, in six Western European countries with a mandatory tax on members of major Christian churches (and in some cases, other religious groups), most adults say they pay it. The share of self-reported church tax payers in these countries ranges from 68% of survey respondents in Sweden to 80% in Denmark, while no more than one-in-five in any country say they used to pay but have stopped.
In addition, among those who say they pay, large majorities describe themselves as “not too” or “not at all” likely to take official steps to avoid paying the tax in the future, including nearly nine-in-ten in Denmark and Finland.That so many people currently pay the church tax helps us understand why the practice remains widespread and is likely to continue for many years into the future.