The "Gesellschaft für deutsche Sprache e. V." ("Society for the
German Language") publishes something that approaches an "official" national statistic. They make public the top 10 names every year, but you can order a list of the top 200 names for a small fee, as described here (in
German):
http://www.gfds.de/index.php?id=63
However, the lists are for personal use only; when I once tried to get a license for publishing the lists as part of my shareware, they declined.
As for
Finn, that looks really strange, and I don't know of anything in the popular culture in Germany right now that could produce this phenomenon. But maybe I am already too old, maybe
German teenagers should be interviewed :)
Rene www.AboutNames.ch