It would be easier to start tracing the data inserted from now on.
The only thing that comes to my mind is the default trace, that is reset every time the service restarts, and, in this case, won't be very useful. I don't think you have any chance to retrieve this kind of information consistently.
I suggest you to try to find a particular pattern in data that can be tied to a single application.
Good Luck!
Gianluca