-53.45% is the change from 840 to 391
Calculation steps:
[( 391 - 840 ) ÷ 840] x 100 = -53.45%
Formula
Percentage change = [(391 - 840) / 840] x 100
Subtract the new number by the original number
391 - 840 = -449
-449 ÷ 840 = -0.5345238095238095
-0.5345238095238095 x 100 = -53.45%