Fly,
There are 30 Daniel Coopers just in Wyoming, 110 in Alaska, 120 in Vermont. There are 8 Daniel Coopers in freaking Guam.
Guam.
Also 5,378 in Pennsylvania alone. Daniel was the 12th most common baby name in the 1970's and Cooper was likely in the top 50 surnames. (70th now)
This year's Best Actor winner at the Oscars played a character named Dan Cooper in a horror movie.
Just saying it's not rare now and was less rare then. I have Daniels and Coopers in my own family.