Same with slavery. Maybe 4.8% of the people in the South owned slaves. But those people had spouses and children who all gained from that person owning the slave.
And what percentage of the Clothes wearing North benefited from purchasing products from the South?
What percentage of the North sold their own slaves in the South rather than take the loss when their state went Abolitionist?
What was the profits to the North Eastern Ship Building Industry which built the slave ships? How much value did the 13 Colonists get out of their slaves when they declared Independence?
You leave out a lot of calculations in your simplistic analysis.
And you do like to twist things into knots. The purpose of this post seemed to be that slavery could not be a cause of the Southern rebellion because so few people owned slaves. It ignores the fact that far more people drew direct benefit from slavery than merely the slave owners. Therefore it makes sense that the South would be willing to rebel to protect it. You, on the other hand, throw in useless questions about the North benefiting from slavery when slavery was not a reason why they fought the war that was forced upon them.
An interesting point I've never been able to find figures on. If you have any, I'd be really interested in seeing them.