Thankfully has now, like hopefully, been widely accepted in normal usage as an adverb that can relate to a whole sentence as well as to a single verb: Thankfully, no damage was done. It is usually easy to distinguish in speech between this sense, meaning ‘fortunately’, and the other sense ‘in a thankful way’: He sank down thankfully into the soft warm bed. In writing, care should be taken to make sure that it is clear which sense is intended