My best friend is one of 11, and he is #6...right in the middle.
When I was a child my mom and aunt took us up into the northern part of the state to meet some distant relatives who lived on a farm. Oh my Dear Lord!!! They scared me. There were 15 children including three sets of twins. Inside the steaming house was a big tin bucket of water with a large ladle and everyone drank from it. I could not, would not, and knew I would find clean water somehow. I was probably around 10. A couple of the 15 showed me how to lower this elongated container down a pipe that went into the ground. That was the well. When the container was pulled back up it had water in it. I remember thinking it was the best water I'd ever had. Perhaps because I was teetering on death by dehydration.
I'm the eldest of seven, my mother's sister has nine, dad was second of nine (then Granddad remarried after Grandma died, his second wife wasn't much older than Dad and they had five more).