It is said that today a university educated Chinese person knows some 5000-6000 different characters. In imperial times when the official language was literary/classical Chinese how many characters did an average scholar (someone who passed the official examinations or a government official for instance) know?
(For reference only)
據了解，在沒有普及教育時，這批識字之人大多是世襲官員，在家裡受教育。 他們在秦與西漢稱為「史」、「卜」及「祝」。 按照職掌任務不同，基本上他們懂三千、五千或七千字，還能背誦文獻。
It is understood that, in the absence of universal education, most of these literate persons were hereditary officials who were educated at home. They were called 史, 卜 and 祝 in the Qin (221–206 BC) and the Western Han (206 BC – 9 AD) Dynasty. In accordance with the different tasks, basically they understood 3,000, 5,000 or 7,000 words, and recited the literature too.
However, 张德芳 said 当时要做“史”得识九千字, which roughly translates into:
At the time, to be a 史，one needed to know 9000 characters.