But those were the people that could actually read and write. Most people were illiterate. Only those privileged with status and wealth could have access to reading materials (and they would be the only people that would even desire them), and they were only men.
The small number is irrelevant. The OP said office jobs did not exist in medieval times. This is quite clearly an incorrect statement. I am perfectly happy to debate whether pointing this out is relevant to the point being made, but I stand by my assertion.