I'm talking about the duration of an uninterrupted stream.
Mine is 73 seconds. I time it (on a watch) occasionally, when I'm out drinking or have been holding it a while and can tell if it's going to be a potential record breaker.
Extending how long you can hold an uninterrupted stream takes some technique, I've found. You have to practice restraint and must be able to recognize the precise moment to let loose, right before your stream threatens to turn into a dribble. (NOTE: The moment it turns into a dribble or series of droplets, the clock stops.)