And that's giving each child their own bedroom and saving one for guests! I grew up with me and two siblings all in the same bedroom. (And honestly, it was alright, I'm probably better for it, and we definitely weren't poor by any measure. So, the figures above should be read as "if we spoil the children", IMO.)
A thing I think is funny is that so many people feel like their kids "need" their own bedroom, then as soon as college rolls around, "dorm life" is completely fine where they have one or more roommates living in a space that is often smaller than what their bedroom back home was.