Population
noun
The amount of people with mouths (that you have to feed) is the population that you have to feed.
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 人 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
Here at Tofugu, we measure population in jeans (じん). Each of us has just one pair of jeans, so if you know the jean count you know the population.
人口のはんぶんはだんせいです。
Half the population is male.
このむらの人口はたったの二十三にんです。
This village's population is only 23.
じぶんのまちの人口をしらないにほんじんはおおい。
Many Japanese people don’t know the population of their own town.