I'm running a premodern setting where the characters will be involved in local administration. Assuming no magic, how many farmers does it take to support one non-farmer? Any statistics/estimates are welcome, from neolithic to renaissance (but preferably between Roman and medieval). A perfect answer would be something like this:
In the Vth century, W farmers could farm X acres of land, growing enough of crop Y for themselves and Z other people.
Perfect accuracy isn't my goal here, I'd just like to get the result close-ish. It's like when you have a soldier or a mining engineer playing your setting — you don't have to get the combat or the mining correct, just not so awful that it gets laughed at.