A lot depends on what your definition of a "Yearbook" is. The USPS started releasing "mint sets" as far back as 1968, as I recall. Then they went to "Stamp Folders" such as depicted below, which I believe started in 1971 or 1972:
It evolved into the present-day hardcover yearbooks. Frankly, the current yearbooks are quite expensive and of minimum philatelic value, so I have not collected them.
In fact, over time, you will find that a lot of collectors strip the stamps out of the older "stamp folders" and in many cases the folders are discarded, as they were never known to use good archival quality mounts and I've actually had some of the mint stamps get damaged by leaving them in the USPS "stamp folders" for extended periods.
Posted 12/25/2010 09:40 am
