In addition to external pressure, domestic policies implemented by the Vietnamese Government since 1975 had proven to be largely ineffective in stimulating the country's economic growth. By building on the Soviet model of central economic planning, Vietnam placed most emphasis on the development of heavy industries, while production in agriculture and light manufacturing sectors stagnated. Furthermore, attempts to nationalise the economy of southern Vietnam after reunification only resulted in chaos, as economic output was driven down by dislocation of the general population. In addition to those failed economic policies, Vietnam maintained the fifth-largest armed forces in the world, with 1.26 million regular soldiers under arms, 180,000 of whom were stationed in Cambodia in 1984. Consequently, the Vietnamese Government had to spend one-third of its budget on the military and the campaign in Kampuchea, despite receiving US$1.2 billion in military aid annually from the Soviet Union, thus further hampering Vietnam's economic rebuilding efforts.