Do you ever wonder how your baby survives on the amount of milk you produce?

My son is 9 months old and has always been a "bigger than average" baby, but I have no idea how. On a good day, I pump about 10-12 ounces while I'm at work (from 9-6 pm). He only drinks about 2-3 ounces at a time from the bottle. He nurses no longer than 10 minutes on average. He doesn't eat many solids.. he never really got into the purée foods. He does still wake up every 3-4 hours to nurse though. We haven't had to supplement with formula (yet) but we have a back up cam at home, because I never know if I'll have enough. Do you ever wonder how your baby survives on your milk?