Final answer:
According to the National Assessment of Adult Literacy, about 12% of American adults have proficient health literacy, indicating they can adequately understand and process health-related information.
Step-by-step explanation:
The National Assessment of Adult Literacy is a nationally representative assessment that evaluates English literacy skills among American adults aged 16 and older. According to their research, approximately 12 percent of adults have 'proficient health literacy', meaning they have the ability to 'obtain, process, and understand basic health information and services needed to make appropriate health decisions.'
Learn more about Health Literacy