What proportion of US government revenue (federal,state,local) came from taxes on slaves between 1790 and 1846?
I chose 1846 as the breakpoint because of the Walker Tariff; feel free to critique that choice.
Based on this paper (h/t to Brian Z), taxes on slaves did not seem to be important for the federal government during this period (unless they were subject to excise?).
This paper discusses "disputes about the taxation of slaves" and seems to imply that they were often taxed as property in southern states. It does not discuss relative magnitudes, but it is what motivated the question.