China has shown a much more flexible approach to foreign trade over the past few years and has adopted a series of measures designed to strengthen international economic cooperation. Foreign countries are encouraged to mount exhibitions of their goods and China itself has participated in a number of trade fairs and exhibitions held abroad. Since the late 1970s China has also adopted foreign trade practices long-established in many other countries. Goods are produced according to a sample provided by the customer, while strong encouragement is given to compensation trade whereby a foreign seller supplies raw materials and equipment and receives manufactured goods, produced by the equipment provided, in return. Compensation trade differs from barter or counter-trade in so far as there is a direct link between the equipment supplied from abroad and the manufactured product. Assembly manufacturing began in 1978 and particular forms of foreign trade are eligible for exemption from customs duties and taxation.