-2.02% is the change from 840 to 823
Calculation steps:
[( 823 - 840 ) ÷ 840] x 100 = -2.02%
Formula
Percentage change = [(823 - 840) / 840] x 100
Subtract the new number by the original number
823 - 840 = -17
-17 ÷ 840 = -0.02023809523809524
-0.02023809523809524 x 100 = -2.02%