the aging of population

• 人口老龄化

the aging of population的用法和样例：

例句

1. China's population is aging at unprecedented levels.
   使中国人口老龄化达到了前所未有的水平。
2. Why is the ageing building population or the changing age demographic important to KONE?
   为什么旧建筑的数量或地域性的人口老龄化对通力如此重要？