You should really read my whole comment instead of jumping on what you guess is in the book and what "study" you think the author performs. As noted in my comm

You should really read my whole comment instead of jumping on what you guess is in the book and what "study" you think the author performs. As noted in my comment, the author looks exclusively at white people. More importantly, he looks at a variety of long term (aka multi-decade) studies from a variety of US sources and analyzes that data. But if you want to keep arguing straw men, please feel free. I won't interrupt further.