In this case, the USDA imposed on the [raisin farming] Hornes a “marketing order” demanding that they turn over 47% of their crop without compensation. The order—a much-criticized New Deal relic—forces raisin “handlers” to reserve a certain percentage of their crop “for the account” of the government-backed Raisin Administrative Committee, enabling the government to control the supply and price of raisins on the market. The RAC then either sells the raisins or simply gives them away to noncompetitive markets—such as federal agencies, charities, and foreign governments—with the proceeds going toward the RAC’s administration costs.
I have seen estimates that a Medieval serf had to pay between 30 and 70 percent of his crop to his master. The RAC seems to be right in line with these numbers.