In addition to this, the South] sent to the North $30,000,000 worth of cotton, which is not counted in the exports. We sent to her $7 or $8,000,000 worth of tobacco, which is
not counted in the exports. We sent naval stores, lumber, rice, and many other minor
articles. There is no doubt that we sent to the North $40,000,000 in addition, but suppose
the amount to be $35,000,000, it will give us a surplus production of $220,000,000. But
the recorded exports of the South now are greater than the whole exports of the United
States in any year before 1856. They are greater than the whole average exports of the
United States for the last twelve years, including the two extraordinary years of 1856 and
1857. They are nearly double the amount of the average exports of the twelve preceding
years. If I am right in my calculations as to $220,000,000 of surplus produce there is not a
nation on the face of the earth, with any numerous population, that can compete with us
in produce per capita
-- South Carolina Senator Hammond's Speech to Congress Regarding Kansas - 3/4/1848
PROMPT. Based on the selection, how does the Northern economy rely on the slave labor of the South?
Use evidence only from the text to support your response.