-30.6% is the change from 840 to 583
Calculation steps:
[( 583 - 840 ) ÷ 840] x 100 = -30.6%
Formula
Percentage change = [(583 - 840) / 840] x 100
Subtract the new number by the original number
583 - 840 = -257
-257 ÷ 840 = -0.305952380952381
-0.305952380952381 x 100 = -30.6%