Founded as an outlet for agricultural and industrial products and as a capital-and-labor market, COMECON, like the Warsaw Pact, binds its members to each other and all of them to the Soviet Union. Long-term trade agreements of five years are usually renewable at the end of each term. It is estimated that 60 to 65 percent of the total foreign trade of each signatory is carried on with other member countries. One of the obvious disadvantages of the organization, however, is the absence of a common market. Trade and commerce between the member countries are carried out on the basis of preference and within the framework of bilateral agreements. Because the loose structure of COMECON does not make for effective regional planning, member countries such as Bulgaria continue to renew bilateral trade agreements within COMECON. The Soviet Union remains Bulgaria's largest foreign market, accounting for more than 50 percent of Bulgarian trade. Bulgaria also agreed to send Bulgarian workers to the Soviet Union for heavy industrial projects. Participation of Bulgaria on a regional level has been confined to a few projects. Among these are a COMECON electric power grid, which serves the western Ukraine, especially the city of Kiev; a Romanian-Bulgarian project to construct a power dam and navigation system for sixty miles along the Danube River; a system of high-speed expressways to connect the capital cities of member countries; a project to modernize steel industries and to reduce production and delivery time; and membership in the International Bank for Economic Cooperation, headed by a former deputy chairman of the Soviet State Bank. United Nations Membership and Participation Bulgaria became a member of the UN on December 14, 1955. Its delegates are active in committee work of the UN organs and subsidiary bodies as well as in deliberations on the floor of the General Assembly. One of its most important committee assignments is to the so-called First Committee, which was established as one of the original six committees under the General Assembly's rules of procedure in 1946. It deals with political and security matters and was headed by Milko Tarabanov, one of five Bulgarian delegates to the UN in the session held from September through December 1972. Available records of General Assembly activities in 1970 showed active participation of Bulgaria's delegates in committee work touching on such matters as the review of administrative tribunal judgments; the question of defining aggression; the peaceful uses of outer space; the peaceful uses of the seabed under international waters; and the implementation of the declaration on the granting of independence to colonial countries and peoples. Bulgaria was particularly interested in the Caribbean territories.