even "fit" people aren't as fast as they believe. If you're a runner and you've never stumbled across a person saying "I bet I could do a lap in *insert a time they most likely couldn't do* easily" then id be surprised. These are the people who think running a 6 minute mile is impressive if they didn't run themselves.
Average time... I'd guess 90 seconds.
** That being said, at 23 years old, I hadn't ran in 4 months. I hopped on the track for the hell of it and hit just over tempo pace for a 400m out of muscle memory, running 73. But I was a college athlete and my career had just ended 4 months ago; crazy how fitness can actually carry over for so long, even when you aren't training. Did it hurt more than it should have? Yes.