The age structure can be divided into three types: young type, adult type and elderly type.

1. Young age structure

Young population age structure is the type of population age structure when the younger population is higher than a certain proportion of the total population. Those with an elderly coefficient below 4, a child coefficient above 40, an old-to-young ratio below 15, and a median age below 20 years old have a young population age structure.

If the population age pyramid is used to represent the population age structure, it is a growing population pyramid. Due to the high birth rate and the large proportion of young people in the population, its tower shape is wide at the bottom and pointed at the top.

2. Adult age structure

The adult population age structure is also called the intermediate age structure, which is the type of population age structure between the young and old age structures.

The elderly coefficient is between 4-7, the youth coefficient is between 30-40, the old-to-young ratio is between 15-30, and the median age is between 20-30 years old, all of which are considered adults The numerical limit of type age structure types. Beyond this quantitative limit, the population either belongs to a young age structure or an old age structure.

If the population age pyramid is used to represent the population age structure, it is a static population pyramid shape. Since there is not much difference in the number of people in each age group, and there is a sharp contraction only in the elderly population, the tower shape is relatively straight.

3. Elderly age structure

The elderly population age structure is a type of population age composition in which the number of older people in the total population is higher than a certain proportion.

The elderly coefficient is above 7, the juvenile coefficient is below 30, the old-to-young ratio is above 30, and the median age is above 30 years old, which are all quantitative expressions of the age structure type of the elderly population.

If the population age pyramid is used to represent the population age structure, it is a reduced population pyramid. As there are fewer and fewer young people and a larger proportion of the population is middle-aged and above, the tower shape is wider at the top and narrower at the bottom.

Introduction to population age structure

Population age structure is also called population age composition, which is the proportion or percentage of each age group in the total population.

Age is the basic natural attribute of the population. Any population group is composed of many people with different ages. The populations of different countries or regions at different points in time always start from the 0-year-old group. , up to a certain highest age group.

The proportion of the population of each age group in the total population constitutes the age structure of the population. The age structure of the population includes:

1. The ratio of the population of childbearing age to the population of non-childbearing age in the current population;

2. The ratio of the population of working age to the population of non-working age;

3. The ratio of children and elderly population, etc.