I found a 1920 ship manifest for a relative that handwritten notations for almost every family group on the page.  I've looked at several articles about such notations and can't find anything that explains this particular format.  The entries are of the form #-######  ##/##/##.  In most cases, the first digit is 2.  The 6 digit number (in one case, it is 7 digits) vary all over the place.  The final numbers look like a date, but the puzzle is that most of the dates, if they are dates, are in the 40s, but this manifest is from 1920.  I would have guessed these might be passport dates or something, but the fact that they are in the 40s, and almost every family group shows such an entry has me puzzled.  I've attached the page for review.  Can anyone explain these notations. 

Thanks for any help on this, and a safe and Happy New Year to all!

Gail Marcus