Age structure represents the number of people of different age groups.  

• This is an important indicator of population composition, since a large size of population in the age group of 15- 59 indicates a large working population (Demographic dividend).  
• A greater proportion of population above 60 years represents an ageing population which requires more expenditure on health care facilities. 

• Similarly high proportion of young population would mean that the region has a high birth rate and the population is youthful. 

Source: NCERT – XII Fundamentals of Human Geography