The Time Department interacts with a large number of States in a wide range of different activities. A summary chart showing some of its technical partnerships with Member States can be downloaded here:
Some technical partnerships with Member States
Of course, since the construction of International Atomic Time (TAI) pre-dates both the BIPM's assumption of responsibility for its calculation (previously carried out by the Bureau International de l'Heure, BIH) and the CIPM Mutual Recognition Arrangement (CIPM MRA), our technical partnerships in the domain of time extend also to other States and other institutes.
The following table indicates the number of States involved in various activities of the Department over the last few years:
Click here for a complete list of the timing centres that maintain a local approximation of UTC (UTC(k)) and/or an independent local time scale (TA(k)).