Customs revenues are traditionally a main source of government income. Guyana uses the common external tariffs (CETs) of CARICOM. Intra-CARICOM trade is free of tariffs. The CET on imports is 5–20%. Consumption taxes are also levied on imports, based on CIF (cost, insurance, and freight) value, but some items are exempted to encourage development. Export taxes range from 0.5% of value to 10%. There is an 80-acre gold export processing zone in Linden.