Some of these codes, those representing countries and territories, were first included as part of the ISO 3166-1 standard in its second edition in 1981, but they have been released by the United Nations Statistics Division since 1970.
Another part of these numeric codes, those representing geographical (continental and sub-continental) supranational regions, was also included in the IANA registry for region subtags (first described in September 2006 in the now obsoleted RFC 4646, but confirmed in its successor RFC 5646, published in September 2009) for use within language tags, as specified in IETF's BCP 47 (where the ISO 3166-1 alpha-2 codes are used as region subtags, instead of UN M.49 codes, for countries and territories).
M.49 area codes (as of 15 April 2009)
Geographical supranational regions (See also BCP 47 where these were imported as region subtags)
Beside the codes standardized above, the numeric codes 900 to 999 are reserved for private-use in ISO 3166-1 (under agreement by the UNSD) and in the UN M.49 standard. They may be used for any other groupings or subdivision of countries, territories and regions.
Some of these private-use codes may be found in some UN statistics reports and databases, for their own specific purpose. They are not portable across databases from third parties (except through private agreement), and may be changed without notice.
Note that the code 000 is reserved and not used for defining any region. It is used in absence of data, or for data in which no region (not even the World as a whole) is applicable. For unknown or unencoded regions, private-use codes should preferably be used.
Extensions to M.49
Early editions of M.49 used one- or two-digit prefixes to designate economic regions rather than assigning 3-digit codes. These two digit prefixes were designed to be used to easily aggregate data through the use of prefix matching, and regions could be specified collectively by using the 000 code as a base to which the prefix would be added. For example, by prefixing 13 to Algeria's code, 012, to create the five-digit code 13012, Algeria could be identified as being in North Africa (13000), which is itself in Africa (10000).
One-digit suffixes were also permitted, to specify statistics of subdivisions of countries. For example, by suffixing 5 to the code for the United Kingdom to create the four-digit code 8265, Scotland could be represented as a subdivision of the United Kingdom. Additional suffixes could be used to represent the other constituent units of the UK.
^Through the second revision of M.49 in 1983, changes in territory did not necessarily result in changed codes.Pakistan, for example, retains the code it was assigned in the original 1970 edition of M.49, even though Bangladesh did not separate from Pakistan until 1971 and did not officially receive a code until the first revision of M.49 was released in 1975.
^The Channel Islands are no longer a political entity, but has been maintained, for statistical use only, in the UN M.49 codification (this grouping has never been encoded in ISO 3166-1, unlike other geopolitical countries or territories), in addition to the newer separate codifications of the Bailiwicks of Jersey and of Guernsey (which were also encoded separately in ISO 3166-1).
^Within the developed regions, Europe is sometimes defined with the exception of Transition countries, numerical code 778.
^ abcdIn international trade statistics, the Southern African Customs Union is also treated as a developed region, and Israel as a developed country in Western Asia.
^ abThe definition of developing countries is not standardized, but it generally excludes the transition countries.
^For some economical analysis, this grouping currently uses the code 019 defined for all Americas, instead of using the code 419 which is assigned to Latin America and the Caribbean
^In some reports, the transition countries may be part of developing countries, or will most often be classed separately from developed and developing countries.
^The selected economical grouping of transition countries of South-eastern Europe is not encoded in UN M.49, but it currently includes Albania and the countries emerging from the former Yugoslavia (with the exception of Slovenia which is now considered as a developed country), for statistical use only.
^Canton and Enderbury Islands (code 128) merged with Kiribati (code 296).
^ abDemocratic Yemen (numerical code 720) and Yemen (886) merged on 22 May 1990 under the name Yemen (887).
^ abThe German Democratic Republic (numerical code 278) accessed on 3 October 1990 to the Federal Republic of Germany (280), with effect from 3 October 1990 and have united to form a single country simply designated as "Germany" (276).
^ abcdUnited States Minor Outlying Islands (numerical code 581) formed by merging Johnston Island (396), Midway Islands (488), United States Miscellaneous Pacific Islands (849), and Wake Island (872).
^The Netherlands Antilles (with previous numerical code 532) was split when Aruba (533) was separated from it, and the remaining part was then given the new numerical code 530.
^Various districts that composed the Trust Territory of the Pacific Islands were split successively from the trusteeship and gained independence to form the Republic of the Marshall Islands (numerical code 584), the Federated States of Micronesia (583), and the Republic of Palau (585). The Commonwealth of the Northern Mariana Islands (580) was later set up in political union with the U.S.
^ abSerbia and Montenegro (numerical code 891) dissolved on 3 June 2006 into 2 independent countries: Montenegro (499) and Serbia (688).
Jensen, O.M.; Parkin, D.M.; MacLennan, R.; Muir, C.S.; Skeet, R.G., eds. (1991), "Appendix 1. United Nations Standard Country Codes"(PDF), Cancer Registration: Principles and Methods, IARC Scientific Publication, International Agency for Research on Cancer, No. 95, pp. 208-211, retrieved 2012
United Nations, Statistics Division (January 1970), United Nations Standard Country Code, Series M: Miscellaneous Statistical Papers, No. 49, New York: United Nations, ST/ESA/STAT/SER.M/49
United Nations, Statistical Office (August 1975), United Nations Standard Area or Country Code for Statistical Use (Rev. 1), Series M: Miscellaneous Statistical Papers, No. 49, New York: United Nations, ST/ESA/STAT/SER.M/49/Rev.1
United Nations, Statistics Office (June 1982), Standard Country or Area Codes for Statistical Use (Rev. 2), Series M: Miscellaneous Statistical Papers, No. 49, New York: United Nations, ST/ESA/STAT/SER.M/49/Rev.2
United Nations, Statistics Division (1996), Standard Country or Area Codes for Statistical Use (Rev. 3), Series M: Miscellaneous Statistical Papers, No. 49, New York: United Nations, ST/ESA/STAT/SER.M/49/Rev.3