Due to technical difficulties beyond my control, my previous post  about a table of energy inputs and outputs for various forms of food production contained description and discussion, but not the table itself. If you're reading this, those difficulties have been resolved. (If you're not reading this, please leave a comment and explain!)
So here it is:
|Hunting and gathering||Pre-industrial agriculture||Industrial agriculture|
|Output/human input ratio||7.8||49.7||4206.0|
Inputs and outputs are in Mj per hectare per year.
Table copyright Michael Common and Sigrid Stagl. Data from Energy and food production, Gerald Leach, IPC Press, 1975.