Barners to agricultural trade durmg the colonial era and up to 1961 were imposed mamly to raise revenue. Accordingly, the barriers were export taxes rather than import tariffs. With the adoption of import substitution as a development philosophy, a more aggressive tariff pohcy was pursued. Thus, s1gn1f1cant increases in tariff rates occurred between 1967 and 1974. The decline in petroleum export earnings of the late 1970s and early 1980s, however, precipitated a rise in protectiomsm in which tanffs were remforced bystrmgent quantitative controls. The effects have been acute shortages of basic commod1ties, unprecedented mflatmn, and growing unemployment.