My paternal grandmother and grandfather were each one of the lucky 2 or 3 children who made it to adulthood in families of 8 - 12 kids. But even reaching adulthood was no guarantee. One of the relatives (the family tree is very confusing, so I'm not sure how they're related) hired help for his wife who was bedridden after her 4th child. The maid was a carrier for typhoid. Both parents and 3 of the kids died.