The Department for Education monitors literacy levels for adults through the Organisation for Economic Co-operation and Development’s (OECD’s) Survey of Adult Skills. The last study took place in 2012 and showed the following:
Percentage of adults (aged 16-65) at each level in literacy in England, 2012
Percentage meeting this level in literacy
Below Level 1
Source: Table 2.7, Adult skills international survey 2012
The survey is available at the following link: https://www.gov.uk/government/publications/international-survey-of-adult-skills-2012.
The next OECD Survey of Adult Skills will take place in 2021/22.