If your Asterisk is logging this, you should find such data in the Attempts page (as lost attempts). Not all version of Asterisk do; in particular, this was missing from 1.0 and 1.2. In 1.4 irt's likely there. Try and look for records which verb is RINGNOANSWER.... on the other side, if you see nothing in QM, likely they are not there, so bad luck for the past.