[jcranmer]

Something important to remember is that the transient documents in the Ancient Mediterranean and Mesopotamian days were scratched into clay (a medium which allows it to be easily erased and adjusted if necessary, and is plentifully available in quantity). One consequence is that if you have these things in a storage building that catches on fire, the clay is baked into pottery and essentially permanently preserved for archaeologists to uncover. Texts written on organic parchment or papyrus are far less durable, as they tend to decompose unless properly stored.

This means we probably have an exaggerated abundance of economic documents due to survivorship bias of the things they wrote economic data on.