longevity

The origin of longevity is long-term. So, when you see longevity, think about it for a long time, in fact, since it existed since the 17th century, the word has some serious longevity. Longevity is most often used to explain the length of a person's life, but it can also mean a long period of time, such as longevity work for a long time for a company.

The term "longevity" may be used as a synonym for "life expectancy" in demographics. However, the term lifetime may refer specifically to members of the long-lived population, mean life expectancy is always statistically defined as the average remaining years of a certain age. For example, life expectancy at birth is the same as the average death age of all people born in the same year (within the cohort). Longevity is most commonly considered to be the general audience's term, which means "typical life span" and specific statistical definitions should be defined as necessary.

An aging population arises from two (possibly related) demographic effects, longevity and declining birthrate. The increase in longevity increases the average age of the population by increasing the number of surviving elderly people. The declining birthrate reduces the number of babies, and as the effect continues, the number of young people generally decreases. Among these two forces, the declining birthrate is the biggest factor in the aging of today's world. More specifically, the overall birthrate fell sharply over the past half century. This is the main reason for the aging of the world's most developed countries. As many developing countries are experiencing a faster birthrate shift, their future population will aging more rapidly than current developed countries.