he 1961 Convention, which was expanded and strengthened by the 1972 Protocol, is considered a major achievement in international drug control because it consolidated all previous conventions and streamlined the international drug control machinery. The 1961 Convention establishes strict controls on the cultivation of opium poppy, coca bush, cannabis plant and their products, which, in the Convention, are described as "narcotic drugs" (although cocaine is a stimulant drug rather than one that induces sleep). Control is exercised over 120 narcotic drugs, mainly natural products, such as opium and its derivatives, morphine, codeine and heroin, but also synthetic drugs, such as methadone and pethidine, as well as cannabis and coca leaf. Parties to the 1961 Convention undertake to limit the production, manufacture, export, import, distribution and stocks of, trade in and use and possession of the con-trolled drugs so that they are used exclusively for medical and scientific purposes. The production and distribution of controlled substances must be licensed and supervised, and Governments must provide estimates and statistical returns to INCB on the forms supplied for that purpose, on the quantities of drugs required, manufactured and utilized and the quantities seized by police and customs officers. The control system established under the 1961 Convention functions well, and the system of estimates first introduced by the 1931 Convention is considered to be the key to that success. The system of estimates covers all States, regardless of whether or not they are parties to the 1961 Convention. Each year, INCB publishes in a technical publication information about the licit movement of the internationally controlled narcotic drugs.