The Agency had established service departments for every belligerent nation in the world; it was therefore able to supply a multitude of families with information, and also to insure for a great many prisoners a correspondence otherwise difficult to establish between them and their families. The 506 to 600 letters which arrived daily in Geneva at the end of 1939 had increased in 1944, according to postal statistics, to a daily mail of 100,000 to 200,000, an average that remained steady at this figure until quite recently. The Agency made three million photocopies and 250 card indexes in which more than thirty million entries are classified, thus making possible the methodical and detailed investigations necessary for the search in each case of a missing person.