https://deadconfederates.com/tag/southern-ports-paid-75-percent-of-tariffs-in-1859/
DeadConfederates.com suggests that Southern ports paid 75% of tariffs. Late to the game but interesting none the less.
The http://books.google.com/books?id=NKcoAAAAYAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=falseThird Annual Report of the Chamber of Commerce of the State of New York may contain additional relevant information.
