Stats are always available to the interviewer in an open-file interview, whereas they are never available in a closed-file interview. (If it's partially closed-file, the interviewer can see your PS and secondary essay, but not your stats).
Just to elaborate on this. There are two types of closed file: completely and partially closed file interviews.
In a partially closed file interview, they have access to only your essays and personal statements, but not your stats. In a completely closed file, they don't even have access to your personal statements and essay. Make sure you check with the school that you interview what type of interview it is (you can even find this information on the interview section on the SDN site).