The islands are all together represented by the ISO 3166-1 alpha-2 code UM. The ISO introduced the term "United States Minor Outlying Islands" in 1986. From 1974 until 1986, five of the islands (Baker Island, Howland Island, Jarvis Island, Palmyra Atoll and Kingman Reef) were grouped under the term "United States Miscellaneous Pacific Islands", with ISO 3166 code PU. The code of Midway Atoll was MI, the code of Johnston Atoll was JT, and the code of Wake Island was WK. The Pacific islands are surrounded by large Exclusive Economic Zones.