That's the problem. Nobody has a number. Originally, and continuously, I'm looking for quantitiative information.
I've seen scores of articles alleging Iodine in walnut, but no quantitiative data or any study.
And Flechas, Abraham, nor any of the other dozen or so MD's, et cet never once mention walnut as a source.
At this stage, my conclusion is that Iodine in walnut is a tall tale (like the existence of love, justice, beauty), but I'm eager to have my perception changed on the subject. Iodine in walnut is in the eyes of the beholder.