The largest demographic of readers, who have the ability to make or break a book is middle class white women. If you can convince them to read your book, you have made it.
I would say it depends on the book. I don't have such data for my Elisp textbook (which fared pretty well), but I'm not sure it would confirm your claim.
mbork_pl|2 years ago
taopai|2 years ago
Sachachua enters this category. I am sure she would be glad to read your book.
pd: sacha if you read this, no offense, just joking, hahahaha