The Iranian Central Oil Fields Company (ICOFC) established in 1999, is one of the five major production companies of the National Iranian Oil Company. It is responsible for production of gas and oil from 68 reservoirs, comprising 43 gas fields and 25 oilfields; among them, 14 gas fields and 9 oilfields are currently in operation, and by the end of the 20 year outlook plan it will have reached 89 fields in 19 provinces.The Company, at its establishment, was assigned to develop and to produce oil and gas from onshore fields through utilization of all available technology and know-how. As of 2015, ICOFC is the largest natural gas producer in Iran.