quota
noun [ C ] uk/ˈkwəʊ.tə/ us/ˈkwoʊ.t̬ə/
定额，限额，配额
a fixed, limited amount or number that is officially allowed
The country now has a quota on immigration. 该国现在对外来移民人数有限额。
figurative The class contains the usual quota (= number) of troublemakers. 班上也有那么些个捣蛋鬼。