The phrase "percent plunge" means a sudden and significant decrease or drop of a certain percentage in something, such as a stock market or a value of something. Full definition
The biggest online subscription video service had been climbing amid a 12 percent plunge in media stocks in the past month. (bloomberg.com)
The company also suffered from a broader drop in shopping - mall traffic, contributing to 11 quarters of same - store sales declines and a 77 percent plunge in profit last year. (bloomberg.com)
But while the drop was anticipated, the recent internal reports showing a 27 percent plunge from last spring's rate elicited an alert from the superintendent directing urgent new steps, including weekly updates from staff and letters sent monthly to parents, starting in February, informing them of the necessary courses that need to be completed. (laschoolreport.com)