How big are binders made?

How many leather 3-ring binders from the 1964 World's Fair were put together? (Made for the producers)?

• I have a leather 3-ring binder that states in gold writing on the front: For those who produced the World's Fair, New York, 1964. Inside are plastic pages with black & white glossy photos of all the displays, maps, etc, also a signed letter from the president of the World's Fair thanking everyone who participated. I have looked on many World's Fair site but never seen anything like this, I know it is rare because it was made just for the producer's and was put together by hand not mass produced. Just wondering how many were made & its potential value as I might sell it.

• Answer:

  it is 10 binders