The labor recruitment law ("muyifa") aimed at replacing corvée labor as a form of tax service with hired labor. Each prefecture calculated the funds needed for official projects in advance so that the funds could be distributed appropriately. The government also paid a premium of 20 percent in years of crop failures. Effectively, it transformed labor service to the government into a monetary payment, increasing tax revenue. However, people who were previously exempt from corvée labor were forced to pay taxes for labor on official projects, and thus protested the new law. Although officially abolished in 1086, the new labor recruitment system existed in practice until the end of the Northern Song dynasty in 1127.