In the 1990s, the North Korean economy saw stagnation turning into crisis. Economic assistance received from the Soviet Union and China was an important factor of its economic growth. Upon its collapse in 1991, the Soviet Union withdrew its support and demanded payment in hard currency for imports. China stepped in to provide some assistance and supplied food and oil, most of it reportedly at concessionary prices. The North Korean economy was undermined and its industrial output began to decline in 1990. Deprived of industrial inputs, including fertilizers, pesticides, and electricity for irrigation, agricultural output also started to decrease even before North Korea had a series of natural disasters in the mid-1990s. This evolution, combined with a series of natural disasters including record floods in 1995, caused one of the worst economic crises in North Korea's history. Other causes of this crisis were high defense spending (about 25% of GDP) and bad governance.