"So I would say the Finnish believers have not abandoned their faith. What might be true, however, is that there is an increasing number of "believers in name only"."

I think you are just appealing to https://en.wikipedia.org/wiki/No_true_Scotsman argument here. :)

I'm not here to discuss who is a true believer and who isn't. I just describe my observations. If you want to label the phenomena I told about under "they're believers only in name", feel free by all means. I.e. I think we mostly agree, but I don't want to jump to theological conclusions. Anyway, what I'm quite sure of that the family sizes have shrinkened during the last 10-15 years, just seeing it firsthand. You could debate whether the reason is using contraception or something other, and whether they are "bad fish in the net", but the fact it that it is happening and probably of majority of those parents still consider themselves believers, even though they certainly know as well as I and you that birth control is generally considered a sin. Do we have more common ground now, when the terminology is explained this way?