-55.92% is the change from 921 to 406
Calculation steps:
[( 406 - 921 ) ÷ 921] x 100 = -55.92%
Formula
Percentage change = [(406 - 921) / 921] x 100
Subtract the new number by the original number
406 - 921 = -515
-515 ÷ 921 = -0.5591748099891423
-0.5591748099891423 x 100 = -55.92%