plummet to… 骤降至

That number rose to 3,900 by 2004 and then plummeted to 760 by 2008.

这个数字在2004年达到了 3900,然后到了 2008年却陡然骤降到760。

近义：drop swiftly to... 快速下降至…

The number of full-time jobs generated by the retail industry dropped swiftly to 14,000.

零售业所提供的全职岗位数量驟降至14000。

反义：go up steeply to… 迅速升至…

Then the interest rate went up steeply to 4.2%.

然后利率迅速升至4.2%。