What fraction of antebellum US national product did the enslaved produce?

This article evaluates the high-profile claim that enslaved African-Americans produced over 50 percent of US national product in the pre-Civil War period. The accounting exercise shows the fraction was closer to (and indeed likely slightly below) the share of the population, that is, about 12.6 percent in 1860. The enslaved population had higher rates of labor force participation, but they were also forced to work in sectors-agriculture and domestic service-with below average output per worker. The economic surplus generated by the enslaved was due chiefly to the low value of the very basic consumption bundle provided rather than to exceptionally high values of production per capita.