The most stricken provinces were Anhui (18% dead), Chongqing (15%), Sichuan (13%), Guizhou (11%) and Hunan (8%). The major contributing factors in the famine were the policies of the Great Leap Forward (1958 to 1962) and people's communes, launched by Mao Zedong, such as inefficient distribution of food within the nation's planned economy; requiring the use of poor agricultural techniques; the Four Pests Campaign that reduced sparrow populations (which disrupted the ecosystem); over-reporting of grain production; and ordering millions of farmers to switch to iron and steel production. During the Seven Thousand Cadres Conference in early 1962, Liu Shaoqi, then President of China, formally attributed 30% of the famine to natural disasters and 70% to man-made errors. After the launch of Reforms and Opening Up, the CCP officially stated in June 1981 that the famine was mainly due to the mistakes of the Great Leap Forward as well as the Anti-Rightist Campaign, in addition to some natural disasters and the Sino-Soviet Split.