It would be easy to assume it skyrocketed as  production peaked and goods became cheaper.

人们很容易假设它随着产量达到顶峰和商品变得更便宜而飙升。

Appalachian coal production peaked in the early 1990s; the EIA forecasts a decline for the next three years, followed by two decades of low-level stability.

阿帕拉契亚的煤炭产量在20世纪90年代初达到顶峰; 美国能源信息管理局预测未来三年煤产量会减少，之后会迎来二十年的低水平稳定期。