practicality...

I have a pile of essays with my name on them. My juniors keep bugging me to get them back. They aren't completely graded, despite the fact that I've had them a week...
I tried to explain to them that they have one to write; I have 25 to grade...didn't make much of an impact on them. I told them I'd give them until Monday to finish their next essay if they give me until Monday to finish grading them...

Anyways, on to my question for blogworld...How long does it usually take you to grade and hand back essays? (They're 2-4 page narratives...25 of them...and I'm a tough grader)