I added some information to the Minigroove (general information) page. I’ve copied and pasted the addition here for your convenience.
From old news paper articles it can be determined that the first 10 and 12 inch albums were released in 1951. It’s an ongoing search to figure out what was released by Philips in which year. It appears to be quite a mess actually.
Recent observations led me to think Philips 07XXX series (for jazz, big band and other more popular genres) were released according to the following scheme:
070XX Most releases before 10/1956
071XX Released from 1956
072XX Released later than 9/1956
073XX Released later than 9/1956
075XX Released later than 9/1956
076XX Most releases before 10/1956
077XX Most releases before 10/1956
This means that the 070XX, 076XX and 077XX ranges were released first, than came 071XX, to be followed by 072XX, 073XX, 075XX.
Sources: My own collection, Discogs and especially the Philips catalog “Amerikanische Serie, hauptcatalog 1956/57”, which lists releases published before Sept. 30, 1956. When going through the pages all I can find are issues from the 070XX, 076XX and 077XX ranges and a few from the 071XX range.
More research is needed though.