The majority of the population in these countries is employed in labor-intensive sectors such as agriculture, manufacturing, and services. Wages and salaries earned by workers in these sectors form a significant portion of national income.
It's important to note that the composition of national income can vary based on the specific characteristics of each country and its stage of development. However, in general, wages and salaries tend to be the largest component of national income in developing countries due to the prominence of labor-intensive sectors.