World Stamp Catalogue/Common themes

It is common for two or more countries to commemorate an event or famous person at the same time by the issue of a stamp.

To accommodate this we will try to co-ordinate the numbering of the stamps when this has occurred. In order to accomplish this we are reserving certain numbers for this purpose. These will be in the range between xxx-yyyy-11nn and xxx-yyyy-19nn, where "xxx" represents the country code, "yyyy" represents the year, and "nn" represents the numbers for the stamps in that set. For a variety of reasons it may not be possible to co-ordinate the numbering of the stamps within a given set, but it will be attempted where it practical to do so.

Numbers	Common theme	Countries	Years	Notes
xxx-yyyy-11nn	New Year	all countries	all years	includes New Years in all calendars
xxx-yyyy-12nn	Europa	all countries of Europe	1956 to present
xxx-1995-15nn	Via Baltica Highway Project	Estonia, Latvia, Lithuanis	1995
xxx-yyyy-19nn	Christmas	all countries	all years	includes other non-christian December festivals and stamps to commemorate the following New Year