The average was 5-7. We ran two sessions at Dragon*Con in Atlanta. Those had about 8-10, if memory serves.
Since the gaming style was less combat-focused, it went smoothly.
But I wouldn't want to try to run a D&D dungeon crawl style of game with the rules we had
Combat was more deadly, too. Taking damage wasn't just ignorable like in D&D. We had 4 tiers of damage. If your HP dropped from the highest to the 2nd highest tier, you took temporary negatives (sustained injuries that made you less combat effective).
At the next tier, you picked up injuries that required treatment or long healing over time/magic to fix (broken bones). At 3rd tier, the injuries could be life threatening over time (internal bleeding). At 4th, permanent (losing a hand in a sword fight, for instance).
So you didn't mess around in fights.
We argued internally about that death spiral, but in a horror system, it made sense.