Hello all, after a search of the rest of my collection, I have now found 2006. I can confirm years 2003 through 2014 from my own collection without interruption.

So, we know they were around for many years and that they are all dated but I still wonder why there are so many of these HKDNP ones out there unless they are used for additional routes. Some of the ones that I had are duplicates and a few are very slightly different in size to their non-HKDNP counterparts.
Again, all of my US-AMS flights do not had HKDNP on them so they are the majority of my collection.

So those two kinds - dated HKDNP and dated non-HKDNP have been discussed a bit but I have not heard anyone speak to the houses that have NO DATES that are sometimes referred to as duplicates by some folks. Does anyone know why they exist/their origin? Thanks!

Thanks!