Census is a whole different animal than the UI unfortunately. The examine window is probably the most heavily hard-coded window in the game in terms of how it all populates.
I did a quick look through the gamedata file just in case and don't see any dynamic data for it either unfortunately (it'd have to be on the examine window, since its part of the item's data rather than character data. Unfortunately it'd be up to Daybreak to add it to the window - on the upside, the amount per planar level has thusfar been consistent, you just can't know if you're partway through without going to the zone and adding one. I just save them up until I have enough for the next level and do them in one big go.