US Department of Education, National Center for Education Statistics.
URL: https://nces.ed.gov/pubs2006/2006483.pdf
Abstract. First release of health literacy results from the 2003 National Assessment of Adult Literacy, measuring the health literacy of adults in the United States across four performance levels. Found 22% of adults had Basic and 14% Below Basic health literacy (36% combined), with the majority (53%) at Intermediate level.