-31.56% is the change from 938 to 642
Calculation steps:
[( 642 - 938 ) ÷ 938] x 100 = -31.56%
Formula
Percentage change = [(642 - 938) / 938] x 100
Subtract the new number by the original number
642 - 938 = -296
-296 ÷ 938 = -0.31556503198294245
-0.31556503198294245 x 100 = -31.56%