North Korea has maintained one of the most closed and centralized economies in the world since the 1940s. For several decades, it followed the Soviet pattern of five-year plans with the ultimate goal of achieving self-sufficiency. Extensive Soviet and Chinese support allowed North Korea to rapidly recover from the Korean War and register very high growth rates. Systematic inefficiency began to arise around 1960, when the economy shifted from the extensive to the intensive development stage. The shortage of skilled labor, energy, arable land and transportation significantly impeded long-term growth and resulted in consistent failure to meet planning objectives. The major slowdown of the economy contrasted with South Korea, which surpassed the North in terms of absolute GDP and per capita income by the 1980s. North Korea declared the last seven-year plan unsuccessful in December 1993 and thereafter stopped announcing plans.