The September Utility Planet, out today, contains the assertion that the number nine ("nueve" in Spanish) rarely appears in Cuban numbers transmissions.
While this was true until fairly recently, a lengthy HM01 project done by this editor shows that the number nine now appears as often as any other.
A note to this effect was put into the October column, which will be out next month, along with a better explanation of how the 5-number groups that designate the digital file transfers often increment each day.
These files are completely binary, and no one in the hobby has successfully decrypted one. There is no telling what's in them.