Fig 2. Percent of low-numerate participants by country income category and (A) educational attainment; (B) age and (C) gender.

Note: According to the World Bank’s classification, low-income countries have a per capita gross national income of less than $1,026, lower middle income countries of $1,026-$3,995, upper middle income countries of $3,996-$12,375, and high-income countries of more than $12,375 [23].