I prefer to think of it in terms of acceptance rate. Yes, 80 to 85% is pretty much the norm in my experience, anthing below 70% is pretty demoralizing but happens on occassion, 90%+ is "rarified air", nice when it happens but not something you can count on. That hasn't changed too much through the years. More noteworthy, though, is that I have found when you get those lower numbers it is a sign of poor mating conditions that will later manifest itself in the coming months in a higher attrition rate among those queens that you do catch. In other words the simple presence of eggs in a nuc 2 weeks after cell insertion does not necessarily a great queen make. I agree with Mike. You really do need to treat your nucs with uniformity, any nuc that hasn't "caught" in the same timeframe as the majority needs to be rebuilt and recelled on the same schedule as all it's neighbors.