"The National Center for Education Statistics (NCES) is the primary federal entity for collecting and analyzing data related to education."

Why don't you believe their numbers?

Oh...you mean the other site... It cites valid data.

"Black, American Indian/Alaskan Native, Hispanic, and Asian/Pacific Islander adults were more likely than White adults to perform in the lowest two literacy levels."

"With one exception, for each racial or ethnic group, individuals born in the United States outperformed those born abroad. The exception occurs among Black adults where there was essentially no difference (only 3 to 7 points)."

"Adults in the lowest level on each of the literacy scales (17 to 19 percent) were far more likely than those in the two highest levels (4 percent) to report receiving food stamps."

"Growing numbers of individuals are expected to be able to attend to multiple features of information in lengthy and sometimes complex displays, to compare and contrast information, to integrate information from various parts of a text or document, to generate ideas and information based on what they read, and to apply arithmetic operations sequentially to solve a problem. The results from this and other surveys, however, indicate that many
adults do not demonstrate these levels of proficiency. Further, the continuing process of demographic, social, and economic change within this country could lead to a more divided society along both racial and socioeconomic lines."

All from https://nces.ed.gov/pubs93/93275.pdf

WHAT do you specifically have a problem with?