Although Madagascar's economy is essentially agricultural, much of the land is unsuitable for cultivation because of its mountainous terrain, extensive laterization, and inadequate or irregular rainfall. Only about 5% of the land area is cultivated at any one time. Despite these figures, agriculture accounts for 30% of GDP and employs about 75% of the work force. Large-scale plantations dominate the production of sisal, sugarcane, tobacco, bananas, and cotton, but, overall, Malagasy agriculture is dependent mainly on small-scale subsistence farmers cultivating less thanoneha (2.47 acres) of land.