-97.72% is the change from 923 to 21
Calculation steps:
[( 21 - 923 ) ÷ 923] x 100 = -97.72%
Formula
Percentage change = [(21 - 923) / 923] x 100
Subtract the new number by the original number
21 - 923 = -902
-902 ÷ 923 = -0.9772481040086674
-0.9772481040086674 x 100 = -97.72%