Question is in the thread title.
There must be BILLIONS (or maybe even a googolplex) of DIP chips that have been placed on boards over the years. It follows that there MUST be some sort of "standard" for the drill bit size; as well as a standard for the through hole plating for the finished size.
Now, I realize that technology over time has changed. So, in addition to the original question, if time matters please include that in the reply. I can very easily believe that this value has gotten smaller over time.
If you don't have an "answer" I'd still appreciate a reply with the value that "you use".