Way too many Nigerians and Somalis in this country for it to be 97% unless we're talking about descending from slaves in Africa...
I've always thought it to be in 80-percent range, but can see 90-ish percent. I've never bought into the 97 percent number but I have seen it tossed around which is why its included. A problem historians get into is absent accurate records you'll see some very broad ranges when it comes to numbers. People killed in a war, a battle, a disease epidemic, etc. They become semi-educated guesses at that point because the data is so incomplete.