The number of years in which the estimated total suppression costs achieves a specific threshold, reflecting low, bad and extreme cost years.

The number of years in which the estimated total suppression costs achieves a specific threshold, reflecting low, bad and extreme cost years.该指标指估算总抑制成本达到特定阈值的年份数量，这些年份的成本分别处于低水平、较差水平与极端水平。