It would obviously be much less than 25%, if you think about the typical blue-collar worker's day a little.
It really depends on the field. If you get someone to work 10 less hours at mcdonalds, you are literally getting 25 percent less out of employing that person, and you need to make up the shortfall with more employees. On the other hand, office work is so independent of hours that many people can work at home with no enforcement just fine.
The last thread didn't fare too badly, I think; let's make it a monthly tradition. (Me, I'm more interested in thinking about real-world policies or philosophies, actual and possible, rather than AI design or physics, and I suspect that many fine, non-mind-killed folks reading LW also are - but might be ashamed to admit it!)
Quoth OrphanWilde:
Let's try to stick to those rules - and maybe make some more if sorely needed.
Oh, and I think that the "Personal is Political" stuff like gender relations, etc also belongs here.