Why is the Snooze Alarm Set at 9 Minutes? [VIDEO]

Did you ever notice how many clocks' default snooze alarm time is nine minutes?

I have often wondered why this is. I asked the Internet. Mostly, I found articles that pointed to someone at some point making the subjective decision that eight minutes was too short, 10 minutes and we could be back in a deep sleep. Then I found this juicy little nugget on the Jewish World Review of all places.

The video shares what I'm talking about.

So, for how long do you set your snooze?