They're using "Black+" as "all Googlers who identify as Black, plus those who identify as Black and any other race". The census does track people identifying w

They're using "Black+" as "all Googlers who identify as Black, plus those who identify as Black and any other race". The census does track people identifying with multiple races. Pew, citing the census, says there are ~46.8M (40.7M + 3.7M + 2.4M) Americans who identify as Black (and possibly as something else as well) so about 14%. [1] https://www.pewresearch.org/social-trends/2021/03/25/the-growing-diversity-of-black-america/#:~:text=In%202019%2C%2040.7%20million%2C%20or,and%20Hispanic%2C%20or%20Black%20Hispanic https://www.pewresearch.org/social-trends/2021/03/25/the-gro.... (Disclosure: I work on ads at Google, speaking only for myself)