
The National Adult Literacy Survey represents 190 million U.S. adults over age sixteen with an average school attendance of 12.4 years. The survey is conducted by the Educational Testing Service of Princeton, New Jersey. It ranks adult Americans into five levels. Here is its 1993 analysis:
National Adult Literacy Survey (NALS) data can be found in Adult Literacy in America, and National Assessment of Education Progress (NAEP) scores can be accessed at this website.