-56.68% is the change from 921 to 399
Calculation steps:
[( 399 - 921 ) ÷ 921] x 100 = -56.68%
Formula
Percentage change = [(399 - 921) / 921] x 100
Subtract the new number by the original number
399 - 921 = -522
-522 ÷ 921 = -0.5667752442996743
-0.5667752442996743 x 100 = -56.68%