Amos, you said, in part:

We use NA for those (not applicable or not available) or UNK.

PLEASE don't use "UNK". Everybody will come to me, asking for the answer!

The practice that I love is putting a paragraph in the eact middle of a blank page that says "This page intentionally left blank" in military documents. Of course it isn't true, since it has that paragraph in it, and furthermore it reveal a terribly authoritarian mindset, I would think.

The purpose for the "intentionally left blank" is to allow room for later addition which will not upset the pagination, as I understand it.

Uncle DaveO (a/k/a UNK)