Table 1 Percentage Distribution of Gross Domestic Product by Sector - 1960, 1965, and 1970 1960 1965 1970* Agriculture 9.8 9.4 7.1 Livestock 5.3 4.2 4.0 Forestry 0.6 0.5 0.4 Fishing 0.2 0.2 0.1 Mining 1.5 1.1 1.0 Petroleum and coal 3.4 3.6 3.8 Petrochemicals t t 0.2 0.5 Manufacturing 19.2 21.1 22.8 Construction 4.1 4.0 4.5 Electrical energy 1.0 1.3 1.8 Communication and transportation 3.3 3.0 3.1 Commerce 31.2 31.7 32.2 Government 4.9 5.6 5.5 Other services 15.5 14.1 13.2 Gross domestic product 100.0% 100.0% 100.0% * Preliminary t Indicates less than 0.1 %. Source: Bank of Mexico. Traditionally, Mexico's mining has been highly concentrated in, and dependent on, silver, lead, zinc, and sulfur. Copper production in Mexico is minimal and in 1970 amounted to only 61,000 metric tons (valued at $70 million) as compared with Arizona's production of 910,000 tons annually. In fact, Mexico accounts for only 1 percent of the world's copper production. Following the Mexicanization of mining in 1961, a general slow-down in exploration occurred. This slow-down, together with fairly level prices for lead and zinc, accounts for the failure of the mining industry to increase the value of metal output. Today, however, there is some indication of renewed interest on the part of foreign mining companies as evidenced by the modest exploration activities of Asarco Mexicana, S.A., Bethlehem Steel, Placer Development, DuPont of Canada, Homestake, and Freeport. Further evidence of this trend is provided by the establishment of exploration groups that are searching for fluorspar, manganese, mercury, and copper, as well as some of the industrial minerals. The great porphry copper province of the southwestern United States is believed to extend for several hundred miles in a southeasterly direction parallel to the West Coast of Mexico. On purely geologic reasoning, it appears that major copper deposits could be located along this trend by employing regional mapping techniques, photogeology, and geochemical prospecting. Other potentially attractive mineral deposits in Mexico could include silver, fluorspar, and perhaps gold. It should be noted that a number of minerals are reserved exclusively for exploitation by the state or by companies having 66 percent Mexican ownership. Those include 5