Source? e.g., Spain 20% Jewish.
Here's what I wrote about the father of Mom's paternal grandmother's mother, too (He's not a Poylisher, though he counts as an Anusi):
Her father "John McCoy" took his wife's surname and was born in Portugal during the Peninsular War, from which his parents fled to the United States; and he met his Ireland-born wife (Mary Ann Elizabeth McCoy, from whom Nana Allen's middle name comes] there. Long story short, he and his wife had a very-nasty divorce (They had some nasty property fight and he is not buried in the McCoy Family Plot in their locality.)
Incidentally, none of Mom's paternal aunts or grandaunts had "Mary", etc. as a first name; and Nana Allen's aunt Mary was named for her mother, as her uncle John was named for his father. Other factors (i.e., besides the naming patterns, nasty divorce, etc.) lead me to believe that he was a Sephardic Crypto Jew. One other factor is that Nana Allen passed down the bubbe meise that we were descended from the Armadan Dark Irish to her younger children [my maternal granddad and her youngest children] though not to the older ones (to whom she told that their great-granddad fled a war from Spain. I found this out when I found Census records and talked to one of Mom's aunts.)
I was writing this, incidentally, when I was explaining why my dog is named Reilly Rosalita. I decided against sending the whole writing because, being a Messianic Jew, I would have risked not getting the tallit that I'm having made for Reilly's bark mitzvah.