In Arkansas, agricultural work accounted for 17% of all prison labor assignments in 2021. https://www.prisonlegalnews.org/media/publications/Captive_L...
17% of prison assignments might be 3 assignments for all I know.
I found a number in your document: "...1.2 million people incarcerated in state and federal prisons, over 65 percent work."
That's 780,000.
And there's 163 million working folks in the USA.
Prisoners power .4% of the economy.