unprecedented rise

基本解释

The recent unprecedented rise that we have seen in agricultural commodity prices is showing no signs of letting up.
我们看到，最近农产品价格空前上涨，而且丝毫没有停止的迹象。
As a matter of fact, the US government cites "the unprecedented rise" of long-term unemployment to justify this decision.
事实上，美国政府这个修正决定就是面对长期失业“前所未有的攀升”而作的。
The length of the downturn (the longest since the Depression) and the weakness of the recovery have combined to generate an unprecedented rise in the rate of long-term unemployment.
低就业率情形延续时间长（自大萧条以来持续走低时间最长）以及回升势头微弱无力的联合作用造就了空前的长期失业率增长。

It should be noted that no Keynesian made a similar contribution to China's unprecedented rise.
ECONOMIST: Letters
The length of the downturn (the longest since the Depression) and the weakness of the recovery have combined to generate an unprecedented rise in the rate of long-term unemployment.
ECONOMIST: Unemployment benefits
As a very substantial part of the baby boom generation moves into retirement, benefit requirements will experience an "extraordinary, unprecedented" rise.
NPR: Alan Greenspan Reflects on Economy's Past, Future