Quite reasonable! It's a SHOCKING claim. First, http://nces.ed.gov/naal/ http://nces.ed.gov/naal/ is the organization I was doing my reading with. Their survey

Quite reasonable! It's a SHOCKING claim. First, http://nces.ed.gov/naal/ http://nces.ed.gov/naal/ is the organization I was doing my reading with. Their surveys span the last 20 years. There's a 200-page PDF describing the surveys. Second, "literacy" is, as you point out, a nuanced term. NAAL has broken it out into 3 categories with 4 rankings possible from Below Basic to Proficient. Based on my reading of the survey questions, I drew the line of "literate" as "proficient". So, http://nces.ed.gov/naal/kf_demographics.asp http://nces.ed.gov/naal/kf_demographics.asp is a summary page, and " Percentage of adults in each prose, document, and quantitative literacy level: 1992 and 2003" is the graph. You can see that the percentages are not collected into a single number. I made the ENTIRELY GROSS assumption that proficiency in one area probably leaks into the other areas. I would like to calculate the actual "Total proficiency" score based on the data though. At any rate, the percentages are abominable.