Yeah, I'm sure they're keeping A LOT of data. Metadata, search history, profiles browsing, app usage times and dates... Unfortunately there's no way to know exactly what data are they hiding, unless you're Zucks or something like that.
As far as I know, living in the EU does help: my understanding is that within the EU, all your data belongs to you even if it's stored by Facebook; as opposed as the US, where Facebook is the rightful owner of the data you provide.