helped their Chinese counterparts formulate the plan. Large numbers of Soviet engineers, technicians, and scientists assisted in developing and installing new heavy industrial facilities, including many entire plants and pieces of equipment purchased from the Soviet Union. Government control over industry was increased during this period by applying financial pressures and inducements to convince owners of private, modern firms to sell them to the state or convert them into joint public-private enterprises under state control. China nationalized commerce, industry, and handicrafts over the period 1953 to 1956. By 1956 approximately 67.5 percent of all modern industrial enterprises were state owned, and 32.5 percent were under joint public-private ownership. No privately owned firms remained. Handicraft industries were organized into cooperatives, which accounted for 91.7 percent of all handicraft workers by 1956. Agriculture underwent extensive organizational changes. In fall 1953, the CCP's Central Committee instituted a state monopoly in purchasing and marketing of grain (and other raw materials). This policy served to break the relationship between wealthy peasants and grain merchants, ending the ability to profit from speculation in grain. To facilitate the mobilization of agricultural resources, improve the efficiency of farming, and increase government access to agricultural products, the authorities encouraged farmers to organize increasingly large and socialized collective units. This collectivization continued over the period 1955 to 1958. From the loosely structured, tiny mutual aid teams, villages were to advance first to lower-stage, agricultural producers' cooperatives, in which families still received some income on the basis of the amount of land they contributed, and eventually to advanced cooperatives, or collectives. In the advanced producers' cooperatives, income shares were based only on the amount of labor contributed. In addition, each family was allowed to retain a small private plot on which to grow vegetables, fruit, and livestock for its own use. The collectivization process began slowly but accelerated in 1955 and 1956. In 1957 about 93.5 percent of all farm households had joined advanced producers' cooperatives. The industrial working class grew from 6 million to 10 million. Industrial work places organized as work units (danwei) provided subsidized housing, permanent jobs, education, and medical care. Great Leap Forward, 1958–60 Before the end of the First Five-Year Plan, the growing imbalance between industrial and agricultural growth, dissatisfaction with inefficiency, and lack of flexibility in the decision-making process convinced the nation's leaders – particularly Mao Zedong – that the highly centralized, industry-based Soviet model