I went to the sleep clinic recently to get my sleep apnea (which I knew I had - it runs in the family) diagnosed and treated. The results: Apparently they consider anything over five episodes of breathing cessation per hour to be a diagnosis of "sleep apnea", and over 30 per hour is "severe". I averaged 130 per hour. That's one-hundred-and-thirty.
My O2 saturation levels were below 90 for 70% of the time I was asleep, and dropped to a low of 53 at one point. It seems to be typically about 80 for people staying at the main Base Camp on Mt. Everest, for crying out loud. I don't know why I haven't just suffocated to death in my sleep before now.