In between occupational structure and development, there is a definite relationship. The higher level of income depends on the higher proportion of population in secondary and tertiary activities. The lower level of income depends upon the higher dependence of population on agriculture or primary activities. That is the only reason that countries where a high proportion of people is engaged in the primary activities, they are counted among the developing countries, e.g. India. The countries where a higher proportion of people is engaged in secondary and tertiary activities, which are counted among the developed countries e.g. USA, Japan etc.