The distribution of the population according to different types of occupation is referred to as the occupational structure.
1. Primary Sector : Agriculture, animal husbandry, forestry, logging, fishery etc. are collectively known as Primary activities. These are primary because production is carried on with the help of nature.
2. Secondary Sector : Manufacturing industries are known as secondary activities. All manufacturing units like small scale industry large scale industry, construction work etc.
3. Tertiary sector : It is a sector which provides services to both primary as well as secondary sector. It include transport, communication, banking, insurance, public administration etc.