ISO 4217 or banking. At the 17th session (February 1978), the related UN/ECE Group of Experts agreed that the three-letter alphabetic codes for International Standard ISO 4217, "Codes for the representation of currencies and funds", would be suitable for use in international trade. Over time, new currencies are created and old currencies are discontinued. Frequently, these changes are due to the formation of new governments, treaties between countries standardizing on a shared currency, or revaluation of an existing currency due to excessive inflation. As a result, the list of codes must be updated from time to time. The ISO 4217 maintenance agency
Regional designations of Montana Zones 3 and 4, with limited areas in zone 5 with a small sliver of the state centered in Sanders County in zone 6. These zone boundaries correspond closely to the Köppen classifications. For purposes of the 2009 International Energy Conservation Code, which provides minimum insulation standards for home construction based on climate, the entire state is classified in climate zone 6, reauiring higher levels of insulation than are recommended in more temperate climates. Regional designations of Montana The Regional designations of Montana vary widely within the U.S state of Montana. The state is a large geographical area () that