The relationship between GDP and literacy rate shows a positive relation between these two factors. This is to say that in those countries where the GDP per capita is higher, their literacy rate is also higher, than in comparison to countries with a lower GDP per capita.
This is an explanation of how societies need education to become more developed and at the same time how a developed society grows based on the education that its citizens received. Both factors are feeding each other to grow or to in-grow.
