The Third Party Congress of the Socialist Unity Party of Germany ("Sozialistische Einheitspartei Deutschlands"—SED) convened in July 1950 and emphasized industrial progress. The industrial sector, employing 40% of the working population, was subjected to further nationalization, which resulted in the formation of the "People's Enterprises" (German: "Volkseigene Betriebe"—VEB). These enterprises incorporated 75% of the industrial sector. The First Five Year Plan (1951–55) introduced centralized state planning; it stressed high production quotas for heavy industry and increased labor productivity. The pressures of the plan caused an exodus of GDR citizens to West Germany. The second SED Party Conference (less important than a party congress) convened from 9–12 July 1952. 1565 delegates, 494 guest-delegates, and over 2500 guests from the GDR and from many countries in the world participated in it. In the conference a new economic policy was adopted, "Planned Construction of Socialism". The plan called to strengthen the state-owned sector of the economy. Further goals were to implement the principles of uniform socialist planning and to use the economic laws of socialism systematically.