It would be an interesting project to contact each manufacturer and get say numbers from 1900 to 2000. Many of them likely have the data in a musty file cabinet somewhere.
And, if not compiled now, it could well be lost forever, as companies get consolidated, and get broken up and sold off for their trademark names.
There obviously would be several spinoff questions, for example, how many bicycle actually made it to the USA.
Also, the "survival rate" of the bicycles. Especially of the quality road bikes vs cheap department store bikes.