At this stage they have to be using numbers of baptised individuals who haven't been df or DA. It's just not possible that numbers have remained at 8 million for the last, well, I don't know how many years.
In fact someone that worked at a branch headquarters (Russian, but possibly worked in Germany, this was before the ban) stated he knew for a fact, because they'd collated figures, that the number was nearer 5 and a half million. And that must have been five years ago.