Evolution of the US Commemorative Yearbooks

USPS started issuing yearbooks for commemorative stamps from 1968.  Later on, the definitive versions were also issued for a few years from 1980 to 1990.  Since 2011 (if I recall correctly), the definitive stamps are included as "section 2" in the yearbook and are called "Mail-use Stamps". 

I collect yearbooks, for two basic reasons: First, they contain all the stamps officially issued in the respective years, so I don't have to research to find out which stamps actually form a complete year set.  Second, the albums have nice illustrations and descriptions of the background of the stamps.  It is simply enjoyable to just grab a yearbook on a Sunday afternoon and read in the couch.  They are usually more detailed and better illustrated than common stamp albums, like Scott and Mystic.

The format of the USPS yearbooks has evolved over the years, from simple, concise in the early years to "luxurious elaborating" more recently.  Up to 1981, the yearbook should be rather called a folder or panel, since it contains only one stock page at the center and descriptions on the two insides of the covers, as pictured below (the 1975 yearbook).  No mounts are used.  One problem is that as many of those yearbooks were manufactured decades ago, the plastic strips are often falling off the page, making some repair work necessary.

Starting from 1982, USPS provides mounts for the stamps included in the yearbook.  The collector needs to moisten the upper half back of the mounts, place the stamps into the mounts, and affix them into the designated places in the yearbook.  This is a better layout than the previous format, and the yearbooks are more aesthetically pleasant with the more detailed stories and pictures.  Up to 1991, the yearbooks are paperback and are housed in plain paper envelopes, although since 1986, the quality of the envelopes had been significantly upgraded.

The yearbooks from 1992 onwards are all in hardcover, much heavier than their predecessors.  They are also housed in dust covers of much better quality.  See pictures below for the 1999 yearbook.  If stamps were the primary pieces of the yearbooks in 70's and 80's, then the book itself has stolen the prime spot since 90's.  They are more like a commercial product than a collectible.  Accordingly, the price of a yearbook has been increasing steadily, from below $5 in early years (except the first three years) to around $140 in 2014 if you get all of the commemorative, definitive, and high-value stamps. 

Surprisingly, most of the earlier yearbooks can be acquired around issuing prices, or even below.  The ones from most recent years have been having steadily high reselling prices.  The only way to explain that is that USPS has issued way too many yearbooks in 70's and 80's, and to some extent, even 90's.