The growth in the number of periodicals published is shown by the following figures taken from Ulrich's International Periodicals Directory.
In 1972 it listed 50,000 periodicals and 20,000 serials. Currently Ulrich's Plus on CD-ROM claims to quickly identify over 200,000 periodicals, (serials, regular and irregular) and annuals published around the world. It also contains 2,569 subject categories and cross-references.
The tenth edition of the Serials Directory published by EBSCO provides access to over 175,000 periodicals, irregular serials, and annuals (including newspapers) from over 250 countries. A source for addresses, telephone and fax numbers of over 86,000 publishers world-wide. The Serials Directory is also a source for more than 11,000 Copyright Clearance Centre registered titles. It is available on CD-ROM or as a five volume hardback edition.
The most comprehensive record of serials past and present is maintained by the ISSN International Centre in Paris, France. This is the organisation responsible for issuing the ISSN (International Standard Serials Number) for serials published in all parts of the world.
Access to the records is available on ISSN Compact - the ISSN Register on CD-ROM including the list of Serials Title Word Abbreviations. This is described as the authoritative world catalogue for serial identification with more than 740,000 entries from 193 countries in 144 languages. There are over 100,000 new and amended records each year.
ISSN Compact is published by Chadwyck-Healey, Ltd.