The average US household has something like 2.5 people in it. It's safe to assume (statistically) that at least two of those people are old enough to consume web content unsupervised.

Then there are edge cases that aren't quite so crazy, like 5 person households where everyone is over the age 14.

So yeah, for one person 50/10 is likely just fine. But for the average household 100/15 is likely closer to baseline.