mortalityn.死亡率；死亡数目；必死性mortality trend死亡率变化趋势mortality model枯损模型mortality chart[经] 死亡率图表mortality ratio人寿险死亡比率mortality curve寿命曲线; 死亡曲线mortality cargo活口货物mortality index失败数mortality factor磨损系数mortality option死亡率期权Mortality causes死因