Spanish abbreviation

I’m trying to interpret the Spanish abbreviation “s.d.” in columns of information. It’s used in an official Mexican record of entrances and exits at the Mexican border. The abbreviation is used in both the “Ocupacion” column and the mode of transportation column. Does it mean “ditto” or “the same as above”?

The record itself.

I don’t think it means ‘ditto’ because the ditto marks are used. Is it possible that it means ‘did not state’? I speak some Spanish but I’m not fluent, all I can think of is ‘sin decir’ but that doesn’t seem very grammatical.

I think it probably means sin datos, “no information.”

This page uses the abbreviation s/d for sin datos.

Good point, Electric Warrior. And that looks like the answer, Colibri, thanks.