Last Updated: Jun 25, 2017 Views: 8
Hello Mr. Bradely,
Thank you for the question! The Pyrex double sprouted measuring cup was released in 1925 and retailed for 50 cents. The sides were tapered a bit and it had a round handle. In 1926 the design was discontinued and a new one with one spout appeared. I took this information from the text : Pyrex By Corning A collectors Guide by Susan Tobier Rogove and Marcia Buan Stienhauer.
I am not sure the total number of items produced or how to determine that. Perhaps you could try an collectors forum or website. I have attached some lists of resources on Pyrex.