Three Words - S8-E16
Continuity mistake: When Mulder sits at the computer terminal in the census records room, we see two empty boxes on the screen, one for an ID and one for a password. The shot cuts to Mulder, then back to the screen and shows him typing the password, while the ID has already been typed in; it is very long and there wasn't time in between shots or nearly enough clicks of keys for Mulder to have entered that ID.
Answer: He was being facetious. He doesn't specifically know that information, he was merely giving examples of the types of information he has access to.
I think so too.
lionhead