I know it is appealing to have "rules" but they really don't exist. The health of a show is not a function of the percentage of gross at all, because it means nothing in the absence of knowing what the show's expenses are. In general, a show is usually healthy if it is in the upper quartile, but not necessarily. Since gross potential varies by theatre, but expenses are only marginally affected by the theatre, it is often true that a theatre is a large venue (e.g., On the Town) may not be in as bad a shape as it seems, if you are looking at the potential, and the reverse can be true in a small theatre. Also, today, the gross potential does not take premium sales into account, so it can be horribly skewed. Earlier, I alluded to the running costs of It's Only a Play, which we know has a sizable salary burden. Then there are shows like Hand to God, with a small cast that is likely earning near the low end, There are also shows with huge operational expenses (e.g., Spider-Man, most famously) that skew way up because of the need for a huge number of stage hands, high maintenance and, if I recall correctly, something like 8 stage managers. Finally, it should be mentioned that these numbers become more significant at the margin, because every show has a stop clause, and the landlord can force it to close (the ultimate unhealthy act) if the revenue falls below it. And that number sometimes conflicts with the producer's interests, such as when a show is not losing money, but it is not making enough money for the landlord. I hope this helps dispel the notion that there is a simple answer to this question.
Updated On: 4/7/15 at 01:33 AM