In 1998, Laos's sown-field area was estimated at 852,000 hectares (2,105,000 acres), or less than 4% of the country's total area. Agriculture accounts for 53% of production and as much as 85% of employment. The main crop is rice, almost entirely of the glutinous variety. Except in northern Laos, where some farmers grow dry rice in forest clearings or on hillsides, most Lao are wetrice farmers. The total area of rice plantings in 1999 was estimated at 718,000 hectares (1,774,000 acres), up from 554,000 hectares (1,369,000 acres) in 1996. Yields, which are relatively low, could be raised substantially through wider use of irrigation and fertilizers. Production, which averaged 609,000 tons annually during 1961–65, rose to 2,103,000 tons in 1999. Less important crops include corn (favored by some upland tribes and stressed by the government as a means of increasing livestock production), manioc, peanuts, and soybeans. The main commercial crops, emphasized by the government as part of its export drive, are coffee, cotton, and tobacco. Also grown are cardamom, tea, ramie, hemp, sugar, bananas, and pineapples. In 2001, the trade deficit for agricultural products was $41 million. The mountain peoples have been known to grow large quantities of opium poppies, sold to dealers in the plains. Opium production was estimated at 200 tons in 2001.