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# Dân số – Tổng cục Thống kê

## Introduction

In this article, we will delve into the fascinating world of demographics, specifically focusing on population statistics. We will explore various aspects such as population averages, urban and rural populations, population density, gender ratios, birth rates, death rates, migration rates, life expectancy, and literacy rates. By understanding these factors, we can gain insights into the development and trends of a nation or region.

## Population Averages

The average population is calculated by determining the average number of inhabitants within a specified period, usually a year. The formula used for this calculation is as follows:

Pt = P0 × ert

Where:

• Pt represents the average population for the given year
• P0 represents the initial population
• e is the natural logarithm base, approximately 2.71828
• r denotes the population growth rate during the specified period
• t signifies the time elapsed from the initial point to the desired point (in years)

## Urban and Rural Populations

The urban population refers to the population residing within the boundaries defined by the state as urban areas, such as districts and towns. On the other hand, the rural population comprises individuals living in areas classified as rural, such as villages.

## Population Density

Population density is the average number of individuals per square kilometer of land. It is calculated by dividing the total population (at a specific time or on average) of a certain area by the land area of that region. Population density can be calculated for different levels, including national, regional (urban and rural), and local (provinces, districts, communes, etc.). This measurement provides insights into the geographical distribution of the population over a specific period.

Population Density (people/km2) = Total population (people) / Land area (km2)

## Gender Ratios

The gender ratio of a population reflects the number of males to 100 females. It is determined using the following formula:

Gender Ratio = Total number of males × 100 / Total number of females

## Gender Ratio of Newborns

The gender ratio of newborns, also known as the sex ratio at birth, indicates the gender balance of newborns during a specific period. It is calculated as the average number of male infants per 100 female infants born during that period.

Gender Ratio of Newborns = Total number of male infants born during the period × 100 / Total number of female infants born during the period

## Birth and Mortality Rates

The crude birth rate is one of the components used for measuring population growth. It indicates the number of live births per 1,000 individuals in a population during a specific period. The formula for calculating the crude birth rate is:

Crude Birth Rate (CBR) = Total number of live births during the period / Population at the time of the study

The total fertility rate (TFR) reflects the average number of children born to a woman (or a group of women) throughout her reproductive years, assuming that she experiences the characteristic birth rates during the study period (ages 15 to 49). If birth rates for specific age groups are calculated (in 5-year ranges), “i” represents the seven age groups: 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, and 45-49. The total fertility rate is calculated using the following formula:

Total Fertility Rate (TFR) = Σ(Bi / Wi) × 5

Where:

• Bi represents the number of live births during the study period for mothers in age group i
• Wi is the number of women in age group i at the time of the study

The coefficient of 5 in the formula is applied to ensure that the average birth rate corresponds to the sum of the characteristic birth rates for each age group stated in the formula.

The crude death rate is one of the components used for measuring population growth. It indicates the number of deaths per 1,000 individuals in a population during a specific period. The formula for calculating the crude death rate is:

Crude Death Rate (CDR) = Total number of deaths during the period / Population at the time of the study

## Child Mortality Rates

Child mortality rates are indicators of the extent of child deaths during the first few years of life. The infant mortality rate (IMR) measures the average number of deaths of infants under one year old per 1,000 live births during the study period. The formula for calculating the infant mortality rate is:

Infant Mortality Rate (IMR) = Total number of infant deaths under one year old during the period × 1000 / Total number of live births during the period

The under-five mortality rate (U5MR) measures the average number of deaths of children under five years old per 1,000 live births during the study period. The formula for calculating the under-five mortality rate is:

Under-Five Mortality Rate (U5MR) = Total number of deaths of children under five years old during the period × 1000 / Total number of live births during the period

## Population Growth Rate

The population growth rate is a crucial indicator of population change during a specific period. The natural increase rate (NIR) is the proportion (per thousand) between the difference of births and deaths compared to the population during the study period. It can also be calculated as the difference between the crude birth rate and the crude death rate of the population during the study period.

NIR = (B – D) / P × 1000

Where:

• B represents the number of live births during the study period
• D represents the number of deaths during the study period
• P represents the population at the time of the study
• CBR represents the crude birth rate
• CDR represents the crude death rate

## Overall Population Growth Rate

The overall population growth rate indicates the percentage increase or decrease in population during the study period.

## Migration Rates

Migration rates provide insights into the movement of individuals from one territorial unit to another. Import rates reflect the number of individuals who migrate from one territory (place of origin) to another during the study period, per 1,000 individuals in the destination territory. On the other hand, export rates reflect the number of individuals who emigrate from a territory during the study period, per 1,000 individuals in the territory of departure.

Import Rate (IR) = Number of immigrants during the study period / Population at the time of the study

Export Rate (OR) = Number of emigrants during the study period / Population at the time of the study

Net migration rate (NR) reflects the immigration and emigration status of a population in a particular territory during the study period. It is calculated as the difference between the number of immigrants and the number of emigrants in a territory, per 1,000 individuals in that territory.

Net Migration Rate (NR) = IR – OR = (I – O) / P × 1000

Where:

• NR represents the net migration rate
• IR represents the import rate
• OR represents the export rate
• I represents the number of immigrants during the study period
• O represents the number of emigrants during the study period
• P represents the population at the time of the study

Or: NR = IR – OR

## Life Expectancy

Life expectancy at birth reflects the estimated number of years a newborn can expect to live if the current mortality pattern continues. It is a vital statistic derived from the life table, which includes data on the probability of surviving from one age to another and the death rates at different ages. The life table provides insights into various stages of life, such as how many individuals will survive to each age, the probability of survival, and mortality rates.

## Literacy Rate

The literacy rate measures the level of literacy, including reading and writing skills, within a population. It is an essential indicator for assessing the educational development of a nation, region, or locality.

The literacy rate is calculated as the percentage of the population aged 15 and above who can read, write, and understand a simple sentence in the national language, ethnic language, or foreign language.

Literacy Rate (%) = Number of individuals aged 15 and above who can read and write / Total population aged 15 and above

## Divorce Statistics

The number of divorce cases during a specific period (usually one calendar year) represents the number of cases legally granted by the court to divorcing couples based on the Marriage and Family Law. This figure does not include separations between married couples.

## Average Age at First Marriage

The average age at first marriage indicates the average number of years an individual remained single before getting married for the first time. This calculation assumes that the proportion of single individuals at each age remains the same as observed during the survey.

## Conclusion

Understanding demographic statistics plays a vital role in evaluating a country’s or region’s progress and development. By analyzing population averages, urban and rural populations, population density, gender ratios, birth rates, death rates, migration rates, life expectancy, and literacy rates, policymakers can make informed decisions to promote social and economic well-being. These statistics provide valuable insights into the trends, challenges, and opportunities faced by societies globally.