Thankfully has been used for centuries to mean ‘in a thankful manner’, as in she accepted the offer thankfully. Since the 1960s it has also been used as a sentence adverb to mean ‘fortunately’, as in thankfully, we didn’t have to wait. Although this use has not attracted the same amount of attention as hopefully, it has been criticized for the same reasons. It is, however, far commoner now than the traditional use, accounting for more than 80 per cent of citations for thankfully in the Oxford English Corpus. For further explanation, see hopefully (usage).