Industry and services employ 65% of North Korea's 12.6 million labor force. Major industries include machine building, military equipment, chemicals, mining, metallurgy, textiles, food processing and tourism. Iron ore and coal production are among the few sectors where North Korea performs significantly better than its southern neighbor—it produces about 10 times more of each resource. Using ex-Romanian drilling rigs, several oil exploration companies have confirmed significant oil reserves in the North Korean shelf of the Sea of Japan, and in areas south of Pyongyang. The agricultural sector was shattered by the natural disasters of the 1990s. Its 3,500 cooperatives and state farms were moderately successful until the mid-1990s but now experience chronic fertilizer and equipment shortages. Rice, corn, soybeans and potatoes are some of the primary crops. A significant contribution to the food supply comes from commercial fishing and aquaculture. Tourism has been a growing sector for the past decade. North Korea has been aiming to increase the number of foreign visitors through projects like the Masikryong Ski Resort.