The population of Japan is decreasing.

The next census will be conducted next year.

Demography is a part of social science that studies the structure, evolution, and problems of human population.

Demography is a branch of social science that studies the structure, distribution, and changes in human population.

Tokyo is the city with the highest population density in Japan.

Looking at the population pyramid, you can see that this country is aging.

Demography is an important tool for understanding various aspects of society.