-30.94% is the change from 921 to 636
Calculation steps:
[( 636 - 921 ) ÷ 921] x 100 = -30.94%
Formula
Percentage change = [(636 - 921) / 921] x 100
Subtract the new number by the original number
636 - 921 = -285
-285 ÷ 921 = -0.30944625407166126
-0.30944625407166126 x 100 = -30.94%