A.5% B.6% C.7% D.8% E.9%
A.5% B.10% C.15% D.20% E.25%
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(zhǎng)壽水平 E.性別比