Thailand's fertile delta region, in combination with its hot and humid climate, makes for very good growing conditions, especially for rice. Archeologists believe that what is now central Thailand was the site of the first true agriculture on the planet and that rice has been cultivated there since between 4000 and 3500 B. C. Agricultural products account for 66 percent of Thailand's exports, and Thailand produces 36 percent of the world's rice. Other important products include coconut, tapioca, rubber, sugar, pineapple, jute, soybeans, and palm oil. Sixty-five percent of the Thai labor force is involved in agriculture.