A.5%~10% B.10%~15% C.15%~20% D.20%~25% E.25%~30%
A.5% B.6% C.7% D.8% E.9%
A.老年人口系數(shù) B.年齡中位數(shù) C.老年人口負(fù)擔(dān)系數(shù) D.長壽水平 E.性別比